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<a href="native__handle__transport_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow-IPC: Core</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span> </div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span><span class="comment">// Not compiled: for documentation only.  Contains concept docs as of this writing.</span></div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#ifndef IPC_DOXYGEN_ONLY</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="keyword">static_assert</span>(<span class="keyword">false</span>, <span class="stringliteral">&quot;As of this writing this is a documentation-only \&quot;header\&quot; &quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span>                       <span class="stringliteral">&quot;(the \&quot;source\&quot; is for humans and Doxygen only).&quot;</span>);</div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="preprocessor">#else </span><span class="comment">// ifdef IPC_DOXYGEN_ONLY</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span> </div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceipc_1_1transport.html">ipc::transport</a></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span>{</div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span> </div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"></span> </div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment">/**</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> * A documentation-only *concept* defining the behavior of an object capable of reliably/in-order *sending* of</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * discrete messages, each containing a native handle, a binary blob, or both.  This is paired with</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * the Native_handle_receiver concept which defines reception of such messages.</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> *</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * ### Concept contents ###</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * The concept defines the following behaviors/requirements.</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> *   - The object has at least 2 states:</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> *     - NULL: Object is not a peer: is not connected/capable of transmission.  Essentially it is not a useful</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> *       state.  A default-cted object is in NULL state; and a moved-from object is as-if default-cted, therefore</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> *       also in a NULL state.  In this state all the transmission methods return `false` and no-op.</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> *     - PEER: Object is or has been a peer (connected/capable of transmission).  It is not possible to exit PEER</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> *       state, except via being moved-from.  A pipe-hosing error retains PEER state for instance.</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *     - Other states are allowed but outside the scope of the concept.  For example a CONNECTING state may or may</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> *       not be relevant (but again not relevant to the concept).</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> *   - The (outgoing) transmission-of-messages methods, including transmission of graceful-close message.</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> *     See their doc headers.</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="comment"> *   - Behavior when the destructor is invoked.  See ~Native_handle_sender()</span></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span><span class="comment"> *     doc header.</span></div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span><span class="comment"> *   - Default ctor (which creates a NULL-state object that can be moved-to and to which &quot;as-if&quot;</span></div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment"> *     state any moved-from object is changed).</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span><span class="comment"> *   - `sync_io`-core adopting ctor (which creates PEER-state object from an idle, as-if-just cted PEER-state</span></div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment"> *     sync_io::Native_handle_sender).</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span><span class="comment"> *   - Move ctor, move assigment operator; these do the reasonable thing including setting the moved-from object</span></div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="comment"> *     to NULL state.  Various satellite APIs (e.g., Native_socket_stream_acceptor) shall</span></div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="comment"> *     need these.  That is such APIs do not rely on the factory/shared-ownership pattern.</span></div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span><span class="comment"> *</span></div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="comment"> * The concept (intentionally) does *not* define the following behaviors:</span></div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span><span class="comment"> *   - How to create a Native_handle_sender, except the default, `sync_io`-core-adopting, and move ctors.</span></div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment"> *     That is it does not define how to create a *new* (not moved-from) and *functioning* (PEER state: transmitting,</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> *     connected) peer object, except the latter from an existing `sync_io`-pattern core.  It only defines behavior</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> *     once the user has access to a Native_handle_sender that is already in PEER state: connected to a opposing</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> *     peer Native_handle_receiver.</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span><span class="comment"> *</span></div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="comment"> * @see Native_socket_stream: as of this writing one key class that implements this concept (and also</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="comment"> *      Native_handle_receiver) -- using the Unix domain socket transport.</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span><span class="comment"> * @see Channel, a pipe-composing class template that potentially implements this concept.</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span><span class="comment"> * @see Blob_sender: a degenerate version of the present concept: capable of transmitting only blobs, not</span></div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="comment"> *      `Native_handle`s.</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"> *</span></div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment"> * @todo In C++20, if/when we upgrade to that, Native_handle_sender (and other such doc-only classes) can become an</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> * actual concept formally implemented by class(es) that, today, implement it via the &quot;honor system.&quot;</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> * Currently it is a class `#ifdef`-ed out from actual compilation but still participating in doc generation.</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> * Note that Doxygen (current version as of this writing: 1.9.3) claims to support doc generation from formal</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> * C++20 concepts.</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> * ### Rationale: Why is send_native_handle() not asynchronous? ###</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> * send_native_handle(), as noted in its doc header (and similarly Blob_sender::send_blob()) has 2 key properties:</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> *   - It will *never* return would-block despite *always* being non-blocking.</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> *   - It takes no completion handler; and it returns pipe-hosing errors synchronously via an out-arg or</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> *     exception.</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> *     - async_end_sending() does take a completion handler.</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> *</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> * That is, it is &quot;somehow&quot; both non-blocking/synchronous -- yet requires no would-block contingency on the user&#39;s</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> * part.  Magical!  How can this possibly work?  After all we know that all known low-level transports will yield</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> * would-block eventually (as of this writing -- Unix domain sockets, POSIX MQs, bipc SHM-based MQs), if the</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> * opposing side is not popping data off the pipe.  Yet, as we look at the opposing Native_handle_receiver concept</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> * we see that it makes no requirement on its impls to pop everything off the low-level transport in-pipe as soon</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> * as it arrives.  (In actual fact all existing impls in Flow-IPC refuse to do any such thing.)</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> *</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> * Naturally the only answer as to how it can work is: Any given Native_handle_sender (and native Blob_sender) impl</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> * shall be ready to encounter would-block internally; if this occurs it will need to make a copy of the offending</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno">   93</span><span class="comment"> * message (the meta-blob part specifically included -- that&#39;s the part that involves significant copying),</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span><span class="comment"> * enqueue it internally -- and keep enqueuing any further send_native_handle()d messages until the would-block</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment"> * clears, and the queue is eventually emptied.</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment"> *</span></div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"> * Fair enough: But isn&#39;t this a performance hazard?  Answer: yes but only in a necessary way.  We reached this</span></div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment"> * decision after considering the entire system end-to-end:</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"> *   -# user prepares message blob B and tells `Native_handle_sender` S to send B;</span></div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"> *   -# S tells low-level transport (possibly kernel) to accept B;</span></div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment"> *   -# `Native_handle_receiver` R pops B from low-level transport;</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment"> *   -# user tells R it wanst to accept B, and R does give the latter to the user.</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment"> *</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment"> * It was a no-go to have Flow-IPC be in charge of allocating either-end buffer for B on the user&#39;s behalf:</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span><span class="comment"> * the user may want to user their own allocator, or the stack, or ??? -- possibly with zero-copy and prefix/postfix</span></div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"> * data nearby.  The user buffer has to be ready, and S and R need to work with the memory areas provided by the</span></div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment"> * user.</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"> *</span></div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"> * Given all that, *one* or more of the following &quot;people&quot; has to be ready to keep B, or a copy of B, around, until</span></div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment"> * the whole thing (1-4) has gone through: the sending user (1 above), S (2 above), or R (3 above).  (If</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"> * the receiving user (4 above) is always receiving things ASAP, without that process being processor-pegged or</span></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span><span class="comment"> * something, then it won&#39;t be a problem: no copying is necessary, except in step 2 when B is copied into</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"> * the low-level process.  Indeed that should be the case usually; we are discussing what to do *if* something goes</span></div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment"> * wrong, or the receivier application is mis-coded, or who knows -- the receiver just isn&#39;t quick enough.)</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno">  115</span><span class="comment"> *</span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment"> * The answer, as already noted: *One* or more of 1, 2, 3 has to make a copy of B long enough until 4 has received it.</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno">  117</span><span class="comment"> * At that point, in terms of overall performance, it *which* one of 1, 2, 3 it should be.  Upon deliberating</span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment"> * a few options occurred, but it seemed clear enough that 1 (original user) should not be the done, if it can be</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno">  119</span><span class="comment"> * helped.  IPC is not networking; as an end user I expect sending an out-message to work synchronously.  Making</span></div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"> * me worry about a completion handler complicates the outgoing-direction API hugely -- and not in a way that</span></div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment"> * makes the incoming-direction API any simpler, since that one always has to be ready for would-block</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno">  122</span><span class="comment"> * (i.e., no in-messages immediately ready -- an async-receive API is required).</span></div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"> *</span></div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment"> * So that left 2 or 3.  I (ygoldfel) simply made the decision that one has to be chosen, and of those 2 is earlier</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> * and (internally for the concept implementer, also me at the time) more straightforward.  If 3 were always</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment"> * reading items out of the low-level transport -- even when the user was not invoking `async_receive_*()` --</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment"> * then it would have to at least sometimes make copies of incoming data before the user chose to pop them out.</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"> * By contrast, queueing it -- only on would-block -- in 2 would effectively make it a last-resort activity, as</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment"> * it should be.</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> *</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> * To summarize: Perfect opposing-receiver behavior cannot be guaranteed, and the low-level transport will eventually</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> * have a limit as to how much data it can buffer =&gt; in that case some entity must make a copy of the overflowing data</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment"> * =&gt; we want to make life easier for end user, so that entity should not be them =&gt; it must be either</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno">  134</span><span class="comment"> * the `*_sender` or `*_receiver` =&gt; we chose `*_sender`, because it is safer and easier and faster and a last resort.</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment"> *</span></div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment"> * One arguable drawback of this API design is that the Native_handle_sender (and Blob_sender) user won&#39;t be</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment"> * informed of an out-pipe-hosing error quite as soon as that object itself would know of it -- in some (rare)</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment"> * cases.  I.e., if some data are queued up during would-block, and the user has stopped doing `send_*()`</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"> * (as far as she is concerned, they&#39;re all working fine and have succeeded), and some timer later</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno">  140</span><span class="comment"> * `*this` determines (in the background now) that the transport is hosed, the user would only find out about it</span></div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"> * upon the next `send_*()` call (it would *then* return the `Error_code` immediately), if any, or via</span></div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment"> * async_end_sending().  Is this really a problem?  Answer: Just... no.  Exercise in reasoning this out (granted</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno">  143</span><span class="comment"> * it is *somewhat* subjective) left to the reader.  (Note we *could* supply some kind of out-of-band</span></div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment"> * on-any-send-error API, and we considered this.  It just was not worth it: inelegant, annoying.  async_end_sending()</span></div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment"> * with its completion handler is well sufficient.)</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno">  146</span><span class="comment"> *</span></div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment"> * It should be noted that this decision to make send_native_handle() synchronous/non-blocking/never-would-blocking</span></div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment"> * has percolated through much of ipc::transport and even ipc::session: all our impls; Blob_sender and all its</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno">  149</span><span class="comment"> * impls; Channel; and quite significantly struc::Channel.  You&#39;ll note struc::Channel::send() is</span></div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment"> * also synchronous/non-blocking/never-would-blocking, and even its implementation at the stage of actually</span></div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment"> * sending binary data via Native_handle_sender/Blob_sender is quite straightforward.  In Flow-IPC a</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno">  152</span><span class="comment"> * `send*()` &quot;just works.&quot;</span></div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment"> *</span></div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment"> * @todo Comparing Blob_sender::send_blob_max_size() (and similar checks in that family of concepts) to test</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno">  155</span><span class="comment"> * whether the object is in PEER state is easy enough, but perhaps we can have a utility that would more</span></div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment"> * expressively describe this check: `in_peer_state()` free function or something?  It can still use the same</span></div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment"> * technique internally.</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno">  158</span><span class="comment"> */</span></div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html">  159</a></span><span class="keyword">class </span><a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a></div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span>{</div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno">  161</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span>  <span class="comment">// Constants.</span></div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment"></span> </div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment">  /// Shared_name relative-folder fragment (no separators) identifying this resource type.  Equals `_receiver`&#39;s.</span></div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a840003f2f91ef73f319e0e6b5e7ab435">  165</a></span><span class="comment"></span>  <span class="keyword">static</span> <span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1util_1_1Shared__name.html">Shared_name</a> <a class="code hl_variable" href="classipc_1_1transport_1_1Native__handle__sender.html#a840003f2f91ef73f319e0e6b5e7ab435">S_RESOURCE_TYPE_ID</a>;</div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span> </div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment"></span> </div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment">   * Default ctor: Creates a peer object in NULL (neither connected nor connecting) state.  In this state,</span></div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment">   * all transmission-related methods (e.g., send_native_handle()) shall return `false` and otherwise no-op</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment">   * (aside from possible logging).</span></div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment">   *</span></div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment">   * This ctor is informally intended for the following uses:</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment">   *   - A moved-from Native_handle_sender (i.e., the `src` arg for move-ctor and move-assignment operator)</span></div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span><span class="comment">   *     becomes as-if defaulted-constructed.</span></div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment">   *   - A target Native_handle_sender for a factory-like method (such as Native_socket_stream_acceptor::async_accept())</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment">   *     shall typically be default-cted by the callin guse.  (E.g.: Native_socket_stream_acceptor shall asynchronously</span></div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment">   *     move-assign a logger-apointed, nicely-nicknamed into that target `*this`, typically default-cted.)</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment">   *</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment">   * ### Informal corollary -- ctor that begins in PEER state ###</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment">   * Any functioning Native_handle_sender shall need at least one ctor that starts `*this` directly in PEER state.</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment">   * In that state the transmission-related methods (e.g., send_native_handle()) shall *not* return `false` and</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment">   * will in fact attempt transmission.  However the form and function of such ctors is entirely dependent on</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment">   * the nature of the low-level transmission medium being encapsulated and is hence *intentionally* not a part</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment">   * of the concept.  That said there is the `sync_io`-core-adopting ctor as well which *is* part of the concept.</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment">   *</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment">   * ### Informal corollary -- NULL-state ctors with 1+ args ###</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment">   * Other, 1+ arg, ctors that similarly create a NULL-state peer object are allowed/encouraged</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment">   * where relevant.  In particular one taking a `Logger*` and a `nickname` string -- so as to subsequently enter a</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment">   * connecting phase via an `*_connect()` method, on the way to PEER state -- is reasonable.</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment">   * However this is not a formal part of this concept and is arguably not a general behavior.</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment">   * Such a ctor is informally intended for the following use at least:</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><span class="comment">   *   - One creates a Native_handle_sender that is `Logger`-appointed and nicely-`nickname`d; then one calls</span></div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment">   *     `*_connect()` on it in order to move it to a connecting phase and, hopefully, PEER state in that order.</span></div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment">   *     It will retain the logger and nickname (or whatever) throughout.</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment">   */</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#abafdb9a1294fe2160c61d48f1cd327ff">  198</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#abafdb9a1294fe2160c61d48f1cd327ff">Native_handle_sender</a>();</div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment"></span> </div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment">   * `sync_io`-core-adopting ctor: Creates a peer object in PEER state by subsuming a `sync_io` core in that state.</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment">   * That core must be as-if-just-cted (having performed no work and not been configured via `.start_*_ops()`).</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span><span class="comment">   * That core object becomes as-if default-cted (therefore in NULL state).</span></div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="comment">   *</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="comment">   * @param sync_io_core_in_peer_state_moved</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment">   *        See above.</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment">   */</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a616a05a623410acde1fc225cbc22f03f">  208</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a616a05a623410acde1fc225cbc22f03f">Native_handle_sender</a>(<a class="code hl_class" href="classipc_1_1transport_1_1sync__io_1_1Native__handle__sender.html">sync_io::Native_handle_sender</a>&amp;&amp; sync_io_core_in_peer_state_moved);</div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment"></span> </div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment">   * Move-constructs from `src`; `src` becomes as-if default-cted (therefore in NULL state).</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment">   *</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment">   * @param src</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment">   *        Source object.  For reasonable uses of `src` after this ctor returns: see default ctor doc header.</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment">   */</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a4348f5448609ef83c53a161e472f85d5">  216</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a4348f5448609ef83c53a161e472f85d5">Native_handle_sender</a>(<a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a>&amp;&amp; src);</div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment"></span> </div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment">  /// Disallow copying.</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a531e4ea9d23cbcb1c456b51b5fa2dca1">  219</a></span><span class="comment"></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a531e4ea9d23cbcb1c456b51b5fa2dca1">Native_handle_sender</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a>&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="comment"></span> </div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment">   * Destroys this peer endpoint which will end the conceptual outgoing-direction pipe (in PEER state, and if it&#39;s</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span><span class="comment">   * still active) and cancels any pending completion handlers by invoking them ASAP with</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span><span class="comment">   * error::Code::S_OBJECT_SHUTDOWN_ABORTED_COMPLETION_HANDLER.</span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment">   * As of this writing these are the completion handlers that would therefore be called:</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment">   *   - The handler passed to async_end_sending(), if it was not `.empty()` and has not yet been invoked.</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment">   *     Since it is not valid to call async_end_sending() more than once, there is at most 1 of these.</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment">   *</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="comment">   * The pending completion handler will be called from an unspecified thread that is not the calling thread.</span></div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span><span class="comment">   * Any associated captured state for that handler will be freed shortly after the handler returns.</span></div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment">   *</span></div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment">   * We informally but very strongly recommend that your completion handler immediately return if the `Error_code`</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="comment">   * passed to it is `error::Code::S_OBJECT_SHUTDOWN_ABORTED_COMPLETION_HANDLER`.  This is similar to what one should</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment">   * do when using boost.asio and receiving the conceptually identical `operation_aborted` error code to an</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment">   * `async_...()` completion handler.  In both cases, this condition means, &quot;we have decided to shut this thing down,</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment">   * so the completion handlers are simply being informed of this.&quot;</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment">   *</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment">   * In NULL state the dtor shall no-op.</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment">   *</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment">   * ### Thread safety ###</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment">   * Same as for the transmission methods.  *Plus* it is not safe to call this from within a completion handler supplied</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment">   * to one of those methods on the same `*this`.  An implication of the latter is as follows:</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment">   *</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment">   * Any user source code line that nullifies a `Ptr` (`shared_ptr`) handle to `*this` should be seen as potentially</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment">   * *synchoronously* invoking this dtor.  (By nullification we mean `.reset()` and anything else that makes the</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment">   * `Ptr` null.  For example destroying a `vector&lt;Ptr&gt;` that contains a `Ptr` pointing to `*this` = nullification.)</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="comment">   * Therefore, if a nullification statement can possibly make the ref-count reach 0, then the user must zealously</span></div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span><span class="comment">   * protect that statement from running concurrently with another send/receive API call on `*this`.  That is to say,</span></div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment">   * informally: When ensuring thread safety with respect to concurrent access to a Native_handle_sender, don&#39;t forget</span></div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment">   * that the destructor also is a write-type of access, and that nullifying a `Ptr` handle to it can synchronously</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment">   * invoke it.</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment">   *</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment">   * @see Native_handle_receiver::~Native_handle_receiver(): sister concept with essentially equal requirements.</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment">   * @see Native_socket_stream::~Native_socket_stream(): implements concept (also implements just-mentioned sister</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment">   *      concept).</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment">   */</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#aa2354a74bc6cdff9389d0b7b642fbadd">  257</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#aa2354a74bc6cdff9389d0b7b642fbadd">~Native_handle_sender</a>();</div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span> </div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment"></span> </div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="comment">   * Move-assigns from `src`; `*this` acts as if destructed; `src` becomes as-if default-cted (therefore in NULL state).</span></div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment">   * No-op if `&amp;src == this`.</span></div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment">   *</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment">   * @see ~Native_handle_sender().</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment">   *</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment">   * @param src</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span><span class="comment">   *        Source object.  For reasonable uses of `src` after this ctor returns: see default ctor doc header.</span></div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment">   * @return `*this`.</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="comment">   */</span></div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a7de1a7f689cfdd926580cf92131896bb">  271</a></span>  <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a>&amp; <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a7de1a7f689cfdd926580cf92131896bb">operator=</a>(<a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a>&amp;&amp; src);</div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span><span class="comment"></span> </div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span><span class="comment">  /// Disallow copying.</span></div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a9a784cf71488184323a79695d45adf2e">  274</a></span><span class="comment"></span>  <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a>&amp; <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a9a784cf71488184323a79695d45adf2e">operator=</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__sender.html">Native_handle_sender</a>&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00275" name="l00275"></a><span class="lineno">  275</span><span class="comment"></span> </div>
<div class="line"><a id="l00276" name="l00276"></a><span class="lineno">  276</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00277" name="l00277"></a><span class="lineno">  277</span><span class="comment">   * In PEER state: Returns max `meta_blob.size()` such that send_native_handle() shall not fail due to too-long</span></div>
<div class="line"><a id="l00278" name="l00278"></a><span class="lineno">  278</span><span class="comment">   * payload with error::Code::S_INVALID_ARGUMENT.  Always the same value once in PEER state.  The opposing</span></div>
<div class="line"><a id="l00279" name="l00279"></a><span class="lineno">  279</span><span class="comment">   * Blob_receiver::receive_meta_blob_max_size() shall return the same value (in the opposing object potentially</span></div>
<div class="line"><a id="l00280" name="l00280"></a><span class="lineno">  280</span><span class="comment">   * in a different process).</span></div>
<div class="line"><a id="l00281" name="l00281"></a><span class="lineno">  281</span><span class="comment">   *</span></div>
<div class="line"><a id="l00282" name="l00282"></a><span class="lineno">  282</span><span class="comment">   * If `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns zero; else</span></div>
<div class="line"><a id="l00283" name="l00283"></a><span class="lineno">  283</span><span class="comment">   * a positive value.</span></div>
<div class="line"><a id="l00284" name="l00284"></a><span class="lineno">  284</span><span class="comment">   *</span></div>
<div class="line"><a id="l00285" name="l00285"></a><span class="lineno">  285</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00286" name="l00286"></a><span class="lineno">  286</span><span class="comment">   */</span></div>
<div class="line"><a id="l00287" name="l00287"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a74452bf96477a7b971e187c67703e8d5">  287</a></span>  <span class="keywordtype">size_t</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a74452bf96477a7b971e187c67703e8d5">send_meta_blob_max_size</a>() <span class="keyword">const</span>;</div>
<div class="line"><a id="l00288" name="l00288"></a><span class="lineno">  288</span><span class="comment"></span> </div>
<div class="line"><a id="l00289" name="l00289"></a><span class="lineno">  289</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00290" name="l00290"></a><span class="lineno">  290</span><span class="comment">   * In PEER state: Synchronously, non-blockingly sends one discrete message, reliably/in-order, to the opposing peer;</span></div>
<div class="line"><a id="l00291" name="l00291"></a><span class="lineno">  291</span><span class="comment">   * the message consists of the provided native handle (if supplied); or the provided binary blob (if supplied);</span></div>
<div class="line"><a id="l00292" name="l00292"></a><span class="lineno">  292</span><span class="comment">   * or both (if both supplied).  The opposing peer&#39;s paired Native_handle_receiver shall receive it reliably and</span></div>
<div class="line"><a id="l00293" name="l00293"></a><span class="lineno">  293</span><span class="comment">   * in-order via Native_handle_receiver::async_receive_native_handle().</span></div>
<div class="line"><a id="l00294" name="l00294"></a><span class="lineno">  294</span><span class="comment">   *</span></div>
<div class="line"><a id="l00295" name="l00295"></a><span class="lineno">  295</span><span class="comment">   * If `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns `false` immediately</span></div>
<div class="line"><a id="l00296" name="l00296"></a><span class="lineno">  296</span><span class="comment">   * instead and otherwise no-ops (logging aside).</span></div>
<div class="line"><a id="l00297" name="l00297"></a><span class="lineno">  297</span><span class="comment">   *</span></div>
<div class="line"><a id="l00298" name="l00298"></a><span class="lineno">  298</span><span class="comment">   * Providing neither a handle nor a blob results in undefined behavior (assertion may trip).</span></div>
<div class="line"><a id="l00299" name="l00299"></a><span class="lineno">  299</span><span class="comment">   * To *not* supply a handle, provide object with `.null() == true`.  To *not* supply a blob, provide</span></div>
<div class="line"><a id="l00300" name="l00300"></a><span class="lineno">  300</span><span class="comment">   * a buffer with `.size() == 0`.</span></div>
<div class="line"><a id="l00301" name="l00301"></a><span class="lineno">  301</span><span class="comment">   *</span></div>
<div class="line"><a id="l00302" name="l00302"></a><span class="lineno">  302</span><span class="comment">   * ### Blob copying behavior; synchronicity/blockingness guarantees ###</span></div>
<div class="line"><a id="l00303" name="l00303"></a><span class="lineno">  303</span><span class="comment">   * If a blob is provided, it need only be valid until this method returns.  The implementation shall, informally,</span></div>
<div class="line"><a id="l00304" name="l00304"></a><span class="lineno">  304</span><span class="comment">   * strive to *not* save a copy of the blob (except into the low-level transport mechanism); but it is *allowed* to</span></div>
<div class="line"><a id="l00305" name="l00305"></a><span class="lineno">  305</span><span class="comment">   * save it if required, such as if the low-level transport mechanism encounteres a would-block condition.</span></div>
<div class="line"><a id="l00306" name="l00306"></a><span class="lineno">  306</span><span class="comment">   *</span></div>
<div class="line"><a id="l00307" name="l00307"></a><span class="lineno">  307</span><span class="comment">   * This means, to the user, that this method is *both* non-blocking *and* synchronous *and* it must not</span></div>
<div class="line"><a id="l00308" name="l00308"></a><span class="lineno">  308</span><span class="comment">   * refuse to send and return any conceptual would-block error (unlike, say, with a typical networked TCP socket API).</span></div>
<div class="line"><a id="l00309" name="l00309"></a><span class="lineno">  309</span><span class="comment">   * Informally, the implementation must deal with any (typically quite rare) internal low-level would-block condition</span></div>
<div class="line"><a id="l00310" name="l00310"></a><span class="lineno">  310</span><span class="comment">   * internally.</span></div>
<div class="line"><a id="l00311" name="l00311"></a><span class="lineno">  311</span><span class="comment">   *</span></div>
<div class="line"><a id="l00312" name="l00312"></a><span class="lineno">  312</span><span class="comment">   * However!  Suppose send_native_handle() returns without error.  This concept does *not* guarantee the message has</span></div>
<div class="line"><a id="l00313" name="l00313"></a><span class="lineno">  313</span><span class="comment">   * been passed to the low-level transport at *this* point in time (informally it shall strive to make that</span></div>
<div class="line"><a id="l00314" name="l00314"></a><span class="lineno">  314</span><span class="comment">   * happen in most cases however).  A low-level would-block condition may cause it to be deferred.  If one</span></div>
<div class="line"><a id="l00315" name="l00315"></a><span class="lineno">  315</span><span class="comment">   * invokes ~Native_handle_sender() (dtor), the message may never be sent.</span></div>
<div class="line"><a id="l00316" name="l00316"></a><span class="lineno">  316</span><span class="comment">   *</span></div>
<div class="line"><a id="l00317" name="l00317"></a><span class="lineno">  317</span><span class="comment">   * However (part II)!  It *is* guaranteed to have been passed to the transport once `*end_sending()`</span></div>
<div class="line"><a id="l00318" name="l00318"></a><span class="lineno">  318</span><span class="comment">   * has been invoked, *and* its `on_done_func()` (if any) callback has been called.  Therefore the expected use</span></div>
<div class="line"><a id="l00319" name="l00319"></a><span class="lineno">  319</span><span class="comment">   * pattern is as follows:</span></div>
<div class="line"><a id="l00320" name="l00320"></a><span class="lineno">  320</span><span class="comment">   *   - Obtain a connected `Native_handle_sender` via factory.</span></div>
<div class="line"><a id="l00321" name="l00321"></a><span class="lineno">  321</span><span class="comment">   *   - Invoke send_native_handle() synchronously, hopefully without error.</span></div>
<div class="line"><a id="l00322" name="l00322"></a><span class="lineno">  322</span><span class="comment">   *   - (Repeat as needed for more such messages.)</span></div>
<div class="line"><a id="l00323" name="l00323"></a><span class="lineno">  323</span><span class="comment">   *   - Invoke `async_end_sending(F)` or `end_sending()` (to send graceful-close).</span></div>
<div class="line"><a id="l00324" name="l00324"></a><span class="lineno">  324</span><span class="comment">   *   - In `F()` destroy the `Native_handle_sender` (its dtor is invoked).</span></div>
<div class="line"><a id="l00325" name="l00325"></a><span class="lineno">  325</span><span class="comment">   *     - `F()` is invoked only once all queued messages, and the graceful-close, have been sent.</span></div>
<div class="line"><a id="l00326" name="l00326"></a><span class="lineno">  326</span><span class="comment">   *</span></div>
<div class="line"><a id="l00327" name="l00327"></a><span class="lineno">  327</span><span class="comment">   * ### Error semantics ###</span></div>
<div class="line"><a id="l00328" name="l00328"></a><span class="lineno">  328</span><span class="comment">   * Firstly: See `flow::Error_code` docs for error reporting semantics (including the exception/code dichotomy).</span></div>
<div class="line"><a id="l00329" name="l00329"></a><span class="lineno">  329</span><span class="comment">   *</span></div>
<div class="line"><a id="l00330" name="l00330"></a><span class="lineno">  330</span><span class="comment">   * Secondly: If the generated #Error_code is error::Code::S_INVALID_ARGUMENT:</span></div>
<div class="line"><a id="l00331" name="l00331"></a><span class="lineno">  331</span><span class="comment">   *   - This refers to an invalid argument to *this* method invocation.  This does *not* hose the pipe:</span></div>
<div class="line"><a id="l00332" name="l00332"></a><span class="lineno">  332</span><span class="comment">   *     further sends, etc., may be attempted with reasonable hope they will succeed.</span></div>
<div class="line"><a id="l00333" name="l00333"></a><span class="lineno">  333</span><span class="comment">   *     - send_meta_blob_max_size() is the limit for `meta_blob.size()`.  Exceeding it leads to `S_INVALID_ARGUMENT`.</span></div>
<div class="line"><a id="l00334" name="l00334"></a><span class="lineno">  334</span><span class="comment">   *       - This interacts with the opposing Native_handle_receiver::async_receive_native_handle() in a subtle</span></div>
<div class="line"><a id="l00335" name="l00335"></a><span class="lineno">  335</span><span class="comment">   *         way.  See &quot;Blob underflow semantics&quot; in that class concept&#39;s doc header.</span></div>
<div class="line"><a id="l00336" name="l00336"></a><span class="lineno">  336</span><span class="comment">   *     - At the impl&#39;s discretion, other conditions *may* lead to `S_INVALID_ARGUMENT`.  If so they must</span></div>
<div class="line"><a id="l00337" name="l00337"></a><span class="lineno">  337</span><span class="comment">   *       be documented.</span></div>
<div class="line"><a id="l00338" name="l00338"></a><span class="lineno">  338</span><span class="comment">   *</span></div>
<div class="line"><a id="l00339" name="l00339"></a><span class="lineno">  339</span><span class="comment">   * Thirdly: All other non-success `Error_code`s generated should indicate the pipe is now indeed hosed; the user</span></div>
<div class="line"><a id="l00340" name="l00340"></a><span class="lineno">  340</span><span class="comment">   * can count on the pipe being unusable from that point on.  (It is recommended they cease to use the pipe</span></div>
<div class="line"><a id="l00341" name="l00341"></a><span class="lineno">  341</span><span class="comment">   * and invoke the destructor to free resources.)  If such a non-success code is emitted, the same one shall be emitted</span></div>
<div class="line"><a id="l00342" name="l00342"></a><span class="lineno">  342</span><span class="comment">   * by all further send_native_handle() and async_end_sending() on `*this`.</span></div>
<div class="line"><a id="l00343" name="l00343"></a><span class="lineno">  343</span><span class="comment">   *</span></div>
<div class="line"><a id="l00344" name="l00344"></a><span class="lineno">  344</span><span class="comment">   * In particular error::Code::S_SENDS_FINISHED_CANNOT_SEND shall indicate that *this* method invocation</span></div>
<div class="line"><a id="l00345" name="l00345"></a><span class="lineno">  345</span><span class="comment">   * occurred after invoking `*end_sending()` earlier.</span></div>
<div class="line"><a id="l00346" name="l00346"></a><span class="lineno">  346</span><span class="comment">   *</span></div>
<div class="line"><a id="l00347" name="l00347"></a><span class="lineno">  347</span><span class="comment">   * No would-block-like error condition shall be emitted.</span></div>
<div class="line"><a id="l00348" name="l00348"></a><span class="lineno">  348</span><span class="comment">   *</span></div>
<div class="line"><a id="l00349" name="l00349"></a><span class="lineno">  349</span><span class="comment">   * Lastly: The implementation is allowed to return a non-`INVALID_ARGUMENT` #Error_code in *this* invocation even</span></div>
<div class="line"><a id="l00350" name="l00350"></a><span class="lineno">  350</span><span class="comment">   * though the true cause is a *previous* invocation of send_native_handle().</span></div>
<div class="line"><a id="l00351" name="l00351"></a><span class="lineno">  351</span><span class="comment">   * Informally this may occur (probably in rare circumstances) if internally the handling of a previous</span></div>
<div class="line"><a id="l00352" name="l00352"></a><span class="lineno">  352</span><span class="comment">   * call had to be deferred due to a low-level would-block condition; in that case the resulting problem is to be</span></div>
<div class="line"><a id="l00353" name="l00353"></a><span class="lineno">  353</span><span class="comment">   * reported opportunistically with the next call.  This allows for the non-blocking/synchronous semantics without</span></div>
<div class="line"><a id="l00354" name="l00354"></a><span class="lineno">  354</span><span class="comment">   * the need to make send_native_handle() asynchronous.</span></div>
<div class="line"><a id="l00355" name="l00355"></a><span class="lineno">  355</span><span class="comment">   *</span></div>
<div class="line"><a id="l00356" name="l00356"></a><span class="lineno">  356</span><span class="comment">   * ### Thread safety ###</span></div>
<div class="line"><a id="l00357" name="l00357"></a><span class="lineno">  357</span><span class="comment">   * You may call this from any thread.  It is *not* required to be safe to call concurrently with</span></div>
<div class="line"><a id="l00358" name="l00358"></a><span class="lineno">  358</span><span class="comment">   * any Native_handle_sender API, including this one and the destructor, invoked on `*this`.</span></div>
<div class="line"><a id="l00359" name="l00359"></a><span class="lineno">  359</span><span class="comment">   *</span></div>
<div class="line"><a id="l00360" name="l00360"></a><span class="lineno">  360</span><span class="comment">   * @param hndl_or_null</span></div>
<div class="line"><a id="l00361" name="l00361"></a><span class="lineno">  361</span><span class="comment">   *        A native handle (a/k/a FD) to send; or none if `hndl_or_null.null() == true`.</span></div>
<div class="line"><a id="l00362" name="l00362"></a><span class="lineno">  362</span><span class="comment">   * @param meta_blob</span></div>
<div class="line"><a id="l00363" name="l00363"></a><span class="lineno">  363</span><span class="comment">   *        A binary blob to send; or none if `meta_blob.size() == 0`.</span></div>
<div class="line"><a id="l00364" name="l00364"></a><span class="lineno">  364</span><span class="comment">   * @param err_code</span></div>
<div class="line"><a id="l00365" name="l00365"></a><span class="lineno">  365</span><span class="comment">   *        See above.</span></div>
<div class="line"><a id="l00366" name="l00366"></a><span class="lineno">  366</span><span class="comment">   * @return `false` if `*this` is not in PEER (connected, transmitting) state;</span></div>
<div class="line"><a id="l00367" name="l00367"></a><span class="lineno">  367</span><span class="comment">   *         otherwise `true`.</span></div>
<div class="line"><a id="l00368" name="l00368"></a><span class="lineno">  368</span><span class="comment">   */</span></div>
<div class="line"><a id="l00369" name="l00369"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#ac96b0aa01c286d525f9dcfa6dacc4220">  369</a></span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#ac96b0aa01c286d525f9dcfa6dacc4220">send_native_handle</a>(<a class="code hl_struct" href="structipc_1_1util_1_1Native__handle.html">Native_handle</a> hndl_or_null, <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">util::Blob_const</a>&amp; meta_blob, <a class="code hl_typedef" href="namespaceipc.html#aa3192e586cc45d3e7c22463bf2760f89">Error_code</a>* err_code = 0);</div>
<div class="line"><a id="l00370" name="l00370"></a><span class="lineno">  370</span><span class="comment"></span> </div>
<div class="line"><a id="l00371" name="l00371"></a><span class="lineno">  371</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00372" name="l00372"></a><span class="lineno">  372</span><span class="comment">   * Equivalent to send_native_handle() but sends a graceful-close message instead of the usual payload; the opposing</span></div>
<div class="line"><a id="l00373" name="l00373"></a><span class="lineno">  373</span><span class="comment">   * peer&#39;s Native_handle_receiver shall receive it reliably and in-order via</span></div>
<div class="line"><a id="l00374" name="l00374"></a><span class="lineno">  374</span><span class="comment">   * Native_handle_receiver::async_receive_native_handle() in the form of</span></div>
<div class="line"><a id="l00375" name="l00375"></a><span class="lineno">  375</span><span class="comment">   * #Error_code = error::Code::S_RECEIVES_FINISHED_CANNOT_RECEIVE.  If invoked after already invoking</span></div>
<div class="line"><a id="l00376" name="l00376"></a><span class="lineno">  376</span><span class="comment">   * `*end_sending()`, the method shall no-op and return `false` and neither an exception nor truthy</span></div>
<div class="line"><a id="l00377" name="l00377"></a><span class="lineno">  377</span><span class="comment">   * `*err_code`.  Otherwise it shall return `true` -- but potentially emit a truthy #Error_code (if an error is</span></div>
<div class="line"><a id="l00378" name="l00378"></a><span class="lineno">  378</span><span class="comment">   * detected).</span></div>
<div class="line"><a id="l00379" name="l00379"></a><span class="lineno">  379</span><span class="comment">   *</span></div>
<div class="line"><a id="l00380" name="l00380"></a><span class="lineno">  380</span><span class="comment">   * In addition: if `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns</span></div>
<div class="line"><a id="l00381" name="l00381"></a><span class="lineno">  381</span><span class="comment">   * `false` immediately instead and otherwise no-ops (logging aside).</span></div>
<div class="line"><a id="l00382" name="l00382"></a><span class="lineno">  382</span><span class="comment">   *</span></div>
<div class="line"><a id="l00383" name="l00383"></a><span class="lineno">  383</span><span class="comment">   * Informally one should think of async_end_sending() as just another message, which is queued after</span></div>
<div class="line"><a id="l00384" name="l00384"></a><span class="lineno">  384</span><span class="comment">   * preceding ones; but: it is the *last* message to be queued by definition.  It&#39;s like an EOF or a TCP-FIN.</span></div>
<div class="line"><a id="l00385" name="l00385"></a><span class="lineno">  385</span><span class="comment">   *</span></div>
<div class="line"><a id="l00386" name="l00386"></a><span class="lineno">  386</span><span class="comment">   * ### Synchronicity/blockingness guarantees ###</span></div>
<div class="line"><a id="l00387" name="l00387"></a><span class="lineno">  387</span><span class="comment">   * async_end_sending() is, unlike send_native_handle(), formally asynchronous.  The reason for this,</span></div>
<div class="line"><a id="l00388" name="l00388"></a><span class="lineno">  388</span><span class="comment">   * and the expected use pattern of async_end_sending() in the context of preceding send_native_handle()</span></div>
<div class="line"><a id="l00389" name="l00389"></a><span class="lineno">  389</span><span class="comment">   * calls, is found in the doc header for Native_handle_sender::send_native_handle().  We omit further discussion here.</span></div>
<div class="line"><a id="l00390" name="l00390"></a><span class="lineno">  390</span><span class="comment">   *</span></div>
<div class="line"><a id="l00391" name="l00391"></a><span class="lineno">  391</span><span class="comment">   * ### Error semantics ###</span></div>
<div class="line"><a id="l00392" name="l00392"></a><span class="lineno">  392</span><span class="comment">   * This section discusses the case where `true` is returned, meaning `*end_sending()` had not already</span></div>
<div class="line"><a id="l00393" name="l00393"></a><span class="lineno">  393</span><span class="comment">   * been called.</span></div>
<div class="line"><a id="l00394" name="l00394"></a><span class="lineno">  394</span><span class="comment">   *</span></div>
<div class="line"><a id="l00395" name="l00395"></a><span class="lineno">  395</span><span class="comment">   * An #Error_code is generated and passed as the sole arg to `on_done_func()`.</span></div>
<div class="line"><a id="l00396" name="l00396"></a><span class="lineno">  396</span><span class="comment">   * A falsy one indicates success.  A truthy one indicates failure; but in particular:</span></div>
<div class="line"><a id="l00397" name="l00397"></a><span class="lineno">  397</span><span class="comment">   *   - error::Code::S_OBJECT_SHUTDOWN_ABORTED_COMPLETION_HANDLER (destructor called, canceling all pending ops;</span></div>
<div class="line"><a id="l00398" name="l00398"></a><span class="lineno">  398</span><span class="comment">   *     spiritually identical to `boost::asio::error::operation_aborted`);</span></div>
<div class="line"><a id="l00399" name="l00399"></a><span class="lineno">  399</span><span class="comment">   *   - other arbitrary codes are possible, as with send_native_handle().</span></div>
<div class="line"><a id="l00400" name="l00400"></a><span class="lineno">  400</span><span class="comment">   *</span></div>
<div class="line"><a id="l00401" name="l00401"></a><span class="lineno">  401</span><span class="comment">   * Reminder: By the nature of `on_done_func()`, the pipe is finished regardless of whether it receives a</span></div>
<div class="line"><a id="l00402" name="l00402"></a><span class="lineno">  402</span><span class="comment">   * success or non-success #Error_code.</span></div>
<div class="line"><a id="l00403" name="l00403"></a><span class="lineno">  403</span><span class="comment">   *</span></div>
<div class="line"><a id="l00404" name="l00404"></a><span class="lineno">  404</span><span class="comment">   * ### Thread safety ###</span></div>
<div class="line"><a id="l00405" name="l00405"></a><span class="lineno">  405</span><span class="comment">   * The notes for send_native_handle() apply.</span></div>
<div class="line"><a id="l00406" name="l00406"></a><span class="lineno">  406</span><span class="comment">   *</span></div>
<div class="line"><a id="l00407" name="l00407"></a><span class="lineno">  407</span><span class="comment">   * @internal</span></div>
<div class="line"><a id="l00408" name="l00408"></a><span class="lineno">  408</span><span class="comment">   * The semantic re. calling `*end_sending()` after already having called it and having that exclusively</span></div>
<div class="line"><a id="l00409" name="l00409"></a><span class="lineno">  409</span><span class="comment">   * return `false` and do nothing was a judgment call.  As of this writing there&#39;s a long-ish comment at the top of</span></div>
<div class="line"><a id="l00410" name="l00410"></a><span class="lineno">  410</span><span class="comment">   * of `&quot;sync_io::Native_socket_stream::Impl::*end_sending()&quot;`&quot; body discussing why I (ygoldfel) went that way.</span></div>
<div class="line"><a id="l00411" name="l00411"></a><span class="lineno">  411</span><span class="comment">   * @endinternal</span></div>
<div class="line"><a id="l00412" name="l00412"></a><span class="lineno">  412</span><span class="comment">   *</span></div>
<div class="line"><a id="l00413" name="l00413"></a><span class="lineno">  413</span><span class="comment">   * @tparam Task_err</span></div>
<div class="line"><a id="l00414" name="l00414"></a><span class="lineno">  414</span><span class="comment">   *         A functor type with signature identical to `flow::async::Task_asio_err`.</span></div>
<div class="line"><a id="l00415" name="l00415"></a><span class="lineno">  415</span><span class="comment">   * @param on_done_func</span></div>
<div class="line"><a id="l00416" name="l00416"></a><span class="lineno">  416</span><span class="comment">   *        See above.  This shall be invoked from an unspecified thread that is not the calling thread.</span></div>
<div class="line"><a id="l00417" name="l00417"></a><span class="lineno">  417</span><span class="comment">   * @return `false` if and only if *either* `*this` is not in PEER (connected, transmitting) state, *or*</span></div>
<div class="line"><a id="l00418" name="l00418"></a><span class="lineno">  418</span><span class="comment">   *         `*end_sending()` has already been called before (so this is a no-op, in both cases).</span></div>
<div class="line"><a id="l00419" name="l00419"></a><span class="lineno">  419</span><span class="comment">   *         Otherwise `true`.</span></div>
<div class="line"><a id="l00420" name="l00420"></a><span class="lineno">  420</span><span class="comment">   */</span></div>
<div class="line"><a id="l00421" name="l00421"></a><span class="lineno">  421</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Task_err&gt;</div>
<div class="line"><a id="l00422" name="l00422"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a4c92fe4e43ddf819a2c767cc53cbe477">  422</a></span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a4c92fe4e43ddf819a2c767cc53cbe477">async_end_sending</a>(Task_err&amp;&amp; on_done_func);</div>
<div class="line"><a id="l00423" name="l00423"></a><span class="lineno">  423</span><span class="comment"></span> </div>
<div class="line"><a id="l00424" name="l00424"></a><span class="lineno">  424</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00425" name="l00425"></a><span class="lineno">  425</span><span class="comment">   * Equivalent to `async_end_sending(F)` wherein `F()` does nothing.</span></div>
<div class="line"><a id="l00426" name="l00426"></a><span class="lineno">  426</span><span class="comment">   *</span></div>
<div class="line"><a id="l00427" name="l00427"></a><span class="lineno">  427</span><span class="comment">   * Informally: If one uses this overload, it is impossible to guarantee everything queued has actually been sent,</span></div>
<div class="line"><a id="l00428" name="l00428"></a><span class="lineno">  428</span><span class="comment">   * as `on_done_func()` is the only mechanism for this.  Most likely this is only useful for test or proof-of-concept</span></div>
<div class="line"><a id="l00429" name="l00429"></a><span class="lineno">  429</span><span class="comment">   * code; production-level robustness typically requires one to ensure everything queued has been sent.  Alternatively</span></div>
<div class="line"><a id="l00430" name="l00430"></a><span class="lineno">  430</span><span class="comment">   * the user&#39;s application-level protocol may already guarantee the message exchange has completed (e.g., by receiving</span></div>
<div class="line"><a id="l00431" name="l00431"></a><span class="lineno">  431</span><span class="comment">   * an acknowledgment message of some sort) -- but in that case one can simply not call `*end_sending()`</span></div>
<div class="line"><a id="l00432" name="l00432"></a><span class="lineno">  432</span><span class="comment">   * at all.</span></div>
<div class="line"><a id="l00433" name="l00433"></a><span class="lineno">  433</span><span class="comment">   *</span></div>
<div class="line"><a id="l00434" name="l00434"></a><span class="lineno">  434</span><span class="comment">   * @return Same as in async_end_sending().</span></div>
<div class="line"><a id="l00435" name="l00435"></a><span class="lineno">  435</span><span class="comment">   */</span></div>
<div class="line"><a id="l00436" name="l00436"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#aa3c2953f7f8a48b8a0cbf49652fb6d41">  436</a></span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#aa3c2953f7f8a48b8a0cbf49652fb6d41">end_sending</a>();</div>
<div class="line"><a id="l00437" name="l00437"></a><span class="lineno">  437</span><span class="comment"></span> </div>
<div class="line"><a id="l00438" name="l00438"></a><span class="lineno">  438</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00439" name="l00439"></a><span class="lineno">  439</span><span class="comment">   * In PEER state: Irreversibly enables periodic auto-pinging of opposing receiver with low-level messages that</span></div>
<div class="line"><a id="l00440" name="l00440"></a><span class="lineno">  440</span><span class="comment">   * are ignored except that they reset any idle timer as enabled via Native_handle_receiver::idle_timer_run()</span></div>
<div class="line"><a id="l00441" name="l00441"></a><span class="lineno">  441</span><span class="comment">   * (or similar).  Auto-pings, at a minimum, shall be sent (subject to internal low-level transport would-block</span></div>
<div class="line"><a id="l00442" name="l00442"></a><span class="lineno">  442</span><span class="comment">   * conditions) at the following times:</span></div>
<div class="line"><a id="l00443" name="l00443"></a><span class="lineno">  443</span><span class="comment">   *   - as soon as possible after a successful auto_ping() call; and subsequently:</span></div>
<div class="line"><a id="l00444" name="l00444"></a><span class="lineno">  444</span><span class="comment">   *   - at such times as to ensure that the time between 2 adjacent sends of *any* message is no more than</span></div>
<div class="line"><a id="l00445" name="l00445"></a><span class="lineno">  445</span><span class="comment">   *     `period`, until `*end_sending()` (if any) or error (if any).</span></div>
<div class="line"><a id="l00446" name="l00446"></a><span class="lineno">  446</span><span class="comment">   * To clarify the 2nd point: If user messages are being sent already, an auto-ping may not be required or may be</span></div>
<div class="line"><a id="l00447" name="l00447"></a><span class="lineno">  447</span><span class="comment">   * delayed until the last-sent message plus `period`).  The implementation shall strive not to wastefully</span></div>
<div class="line"><a id="l00448" name="l00448"></a><span class="lineno">  448</span><span class="comment">   * add auto-ping traffic unnecessary to this goal but is not *required* to do so.  However, per the 1st point,</span></div>
<div class="line"><a id="l00449" name="l00449"></a><span class="lineno">  449</span><span class="comment">   * an auto-ping shall be sent near auto_ping() time to establish a baseline.</span></div>
<div class="line"><a id="l00450" name="l00450"></a><span class="lineno">  450</span><span class="comment">   *</span></div>
<div class="line"><a id="l00451" name="l00451"></a><span class="lineno">  451</span><span class="comment">   * If `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns `false` immediately</span></div>
<div class="line"><a id="l00452" name="l00452"></a><span class="lineno">  452</span><span class="comment">   * instead and otherwise no-ops (logging aside).  If auto_ping() has already been called successfuly,</span></div>
<div class="line"><a id="l00453" name="l00453"></a><span class="lineno">  453</span><span class="comment">   * subsequently it will return `false` and no-op (logging aside).  If `*end_sending()` has been called succesfully,</span></div>
<div class="line"><a id="l00454" name="l00454"></a><span class="lineno">  454</span><span class="comment">   * auto_ping() will return `false` and no-op (logging side).</span></div>
<div class="line"><a id="l00455" name="l00455"></a><span class="lineno">  455</span><span class="comment">   *</span></div>
<div class="line"><a id="l00456" name="l00456"></a><span class="lineno">  456</span><span class="comment">   * ### Behavior past `*end_sending()` ###</span></div>
<div class="line"><a id="l00457" name="l00457"></a><span class="lineno">  457</span><span class="comment">   * As noted: auto_ping() returns `false` and no-ops if invoked after successful `*end_sending()`.</span></div>
<div class="line"><a id="l00458" name="l00458"></a><span class="lineno">  458</span><span class="comment">   * Rationale: If `*end_sending()` has been called, then the receiver shall (assuming no other error) receive</span></div>
<div class="line"><a id="l00459" name="l00459"></a><span class="lineno">  459</span><span class="comment">   * graceful-close (and hose the in-pipe as a result) as soon as possible, or it has already received it</span></div>
<div class="line"><a id="l00460" name="l00460"></a><span class="lineno">  460</span><span class="comment">   * (and hosed the pipe).  Therefore any potential &quot;further&quot; hosing of the pipe due to idle timer would be redundant</span></div>
<div class="line"><a id="l00461" name="l00461"></a><span class="lineno">  461</span><span class="comment">   * and ignored anyway given the nature of the Native_handle_receiver (and similar) API.</span></div>
<div class="line"><a id="l00462" name="l00462"></a><span class="lineno">  462</span><span class="comment">   *</span></div>
<div class="line"><a id="l00463" name="l00463"></a><span class="lineno">  463</span><span class="comment">   * ### Thread safety ###</span></div>
<div class="line"><a id="l00464" name="l00464"></a><span class="lineno">  464</span><span class="comment">   * The notes for send_native_handle() apply.</span></div>
<div class="line"><a id="l00465" name="l00465"></a><span class="lineno">  465</span><span class="comment">   *</span></div>
<div class="line"><a id="l00466" name="l00466"></a><span class="lineno">  466</span><span class="comment">   * @param period</span></div>
<div class="line"><a id="l00467" name="l00467"></a><span class="lineno">  467</span><span class="comment">   *        Pinging occurs so as to cause the opposing receiver to receive *a* message (whether auto-ping or user</span></div>
<div class="line"><a id="l00468" name="l00468"></a><span class="lineno">  468</span><span class="comment">   *        message) at least this frequently, subject to limitations of the low-level transport.</span></div>
<div class="line"><a id="l00469" name="l00469"></a><span class="lineno">  469</span><span class="comment">   *        The optional default is chosen by the impl to most reasonably work with the opposing `idle_timer_run()`</span></div>
<div class="line"><a id="l00470" name="l00470"></a><span class="lineno">  470</span><span class="comment">   *        to detect a zombified/overloaded peer.</span></div>
<div class="line"><a id="l00471" name="l00471"></a><span class="lineno">  471</span><span class="comment">   * @return `false` if `*this` is not in PEER (connected, transmitting) state, or if already called successfully</span></div>
<div class="line"><a id="l00472" name="l00472"></a><span class="lineno">  472</span><span class="comment">   *         in `PEER` state, or if `*end_sending()` was called successfully in `PEER` state; otherwise `true`.</span></div>
<div class="line"><a id="l00473" name="l00473"></a><span class="lineno">  473</span><span class="comment">   */</span></div>
<div class="line"><a id="l00474" name="l00474"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__sender.html#a8a2f1282c18faec36aabf29c99b87054">  474</a></span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__sender.html#a8a2f1282c18faec36aabf29c99b87054">auto_ping</a>(<a class="code hl_typedef" href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">util::Fine_duration</a> period = default_value);</div>
<div class="line"><a id="l00475" name="l00475"></a><span class="lineno">  475</span>}; <span class="comment">// class Native_handle_sender</span></div>
<div class="line"><a id="l00476" name="l00476"></a><span class="lineno">  476</span><span class="comment"></span> </div>
<div class="line"><a id="l00477" name="l00477"></a><span class="lineno">  477</span><span class="comment">/**</span></div>
<div class="line"><a id="l00478" name="l00478"></a><span class="lineno">  478</span><span class="comment"> * A documentation-only *concept* defining the behavior of an object capable of reliably/in-order *receiving* of</span></div>
<div class="line"><a id="l00479" name="l00479"></a><span class="lineno">  479</span><span class="comment"> * discrete messages, each containing a native handle, a binary blob, or both.  This is paired with</span></div>
<div class="line"><a id="l00480" name="l00480"></a><span class="lineno">  480</span><span class="comment"> * the Native_handle_sender concept which defines sending of such messages.</span></div>
<div class="line"><a id="l00481" name="l00481"></a><span class="lineno">  481</span><span class="comment"> *</span></div>
<div class="line"><a id="l00482" name="l00482"></a><span class="lineno">  482</span><span class="comment"> * Concept contents</span></div>
<div class="line"><a id="l00483" name="l00483"></a><span class="lineno">  483</span><span class="comment"> * ----------------</span></div>
<div class="line"><a id="l00484" name="l00484"></a><span class="lineno">  484</span><span class="comment"> * The concept defines the following behaviors/requirements.</span></div>
<div class="line"><a id="l00485" name="l00485"></a><span class="lineno">  485</span><span class="comment"> *   - The object has at least 2 states, NULL and PEER.  See notes in Native_handle_sender w/r/t this;</span></div>
<div class="line"><a id="l00486" name="l00486"></a><span class="lineno">  486</span><span class="comment"> *     they apply equally here.</span></div>
<div class="line"><a id="l00487" name="l00487"></a><span class="lineno">  487</span><span class="comment"> *   - The (incoming) transmission-of-messages methods, including reception of graceful-close message and</span></div>
<div class="line"><a id="l00488" name="l00488"></a><span class="lineno">  488</span><span class="comment"> *     cutting off any further receiving.  See their doc headers.</span></div>
<div class="line"><a id="l00489" name="l00489"></a><span class="lineno">  489</span><span class="comment"> *   - Behavior when the destructor is invoked.  See ~Native_handle_receiver() doc header.</span></div>
<div class="line"><a id="l00490" name="l00490"></a><span class="lineno">  490</span><span class="comment"> *   - Default ctor.  See notes in Native_handle_sender w/r/t this; they apply equally here.</span></div>
<div class="line"><a id="l00491" name="l00491"></a><span class="lineno">  491</span><span class="comment"> *   - `sync_io`-core adopting ctor.  Same deal.</span></div>
<div class="line"><a id="l00492" name="l00492"></a><span class="lineno">  492</span><span class="comment"> *   - Move ctor, move assigment operator.  Same deal.</span></div>
<div class="line"><a id="l00493" name="l00493"></a><span class="lineno">  493</span><span class="comment"> *</span></div>
<div class="line"><a id="l00494" name="l00494"></a><span class="lineno">  494</span><span class="comment"> * The concept (intentionally) does *not* define the following behaviors:</span></div>
<div class="line"><a id="l00495" name="l00495"></a><span class="lineno">  495</span><span class="comment"> *   - How to create a Native_handle_receiver, except the default, `sync_io`-core-adopting, and move ctors.</span></div>
<div class="line"><a id="l00496" name="l00496"></a><span class="lineno">  496</span><span class="comment"> *     Notes for Native_handle_sender apply equally here.</span></div>
<div class="line"><a id="l00497" name="l00497"></a><span class="lineno">  497</span><span class="comment"> *</span></div>
<div class="line"><a id="l00498" name="l00498"></a><span class="lineno">  498</span><span class="comment"> * @see Native_socket_stream: as of this writing one key class that implements this concept (and also</span></div>
<div class="line"><a id="l00499" name="l00499"></a><span class="lineno">  499</span><span class="comment"> *      Native_handle_sender) -- using the Unix domain socket transport.</span></div>
<div class="line"><a id="l00500" name="l00500"></a><span class="lineno">  500</span><span class="comment"> * @see Channel, a pipe-composing class template that potentially implements this concept.</span></div>
<div class="line"><a id="l00501" name="l00501"></a><span class="lineno">  501</span><span class="comment"> * @see Blob_receiver: a degenerate version of the present concept: capable of transmitting only blobs, not</span></div>
<div class="line"><a id="l00502" name="l00502"></a><span class="lineno">  502</span><span class="comment"> *      `Native_handle`s.</span></div>
<div class="line"><a id="l00503" name="l00503"></a><span class="lineno">  503</span><span class="comment"> *</span></div>
<div class="line"><a id="l00504" name="l00504"></a><span class="lineno">  504</span><span class="comment"> * Blob underflow semantics</span></div>
<div class="line"><a id="l00505" name="l00505"></a><span class="lineno">  505</span><span class="comment"> * ------------------------</span></div>
<div class="line"><a id="l00506" name="l00506"></a><span class="lineno">  506</span><span class="comment"> * This potentially important subtlety is regarding the interplay between</span></div>
<div class="line"><a id="l00507" name="l00507"></a><span class="lineno">  507</span><span class="comment"> * Native_handle_receiver::S_META_BLOB_UNDERFLOW_ALLOWED, async_receive_native_handle() `meta_blob.size()`,</span></div>
<div class="line"><a id="l00508" name="l00508"></a><span class="lineno">  508</span><span class="comment"> * and Native_handle_sender::send_native_handle() `meta_blob.size()`.</span></div>
<div class="line"><a id="l00509" name="l00509"></a><span class="lineno">  509</span><span class="comment"> *</span></div>
<div class="line"><a id="l00510" name="l00510"></a><span class="lineno">  510</span><span class="comment"> * Consider a `*this` named `R` and an opposing `*_sender` named `S`.  Note that `R.receive_meta_blob_max_size()</span></div>
<div class="line"><a id="l00511" name="l00511"></a><span class="lineno">  511</span><span class="comment"> * == S.send_meta_blob_max_size()`; call this limit `L`.  `L` shall always be in practice small enough to where</span></div>
<div class="line"><a id="l00512" name="l00512"></a><span class="lineno">  512</span><span class="comment"> * allocating a buffer of this size as the receive target is reasonable; hence kilobytes at most, not megabytes.</span></div>
<div class="line"><a id="l00513" name="l00513"></a><span class="lineno">  513</span><span class="comment"> * (In some cases, such as with `Blob_stream_mq_*`, it is configurable at runtime.  In others, as with</span></div>
<div class="line"><a id="l00514" name="l00514"></a><span class="lineno">  514</span><span class="comment"> * Native_socket_stream, it is a constant: sync_io::Native_socket_stream::S_MAX_META_BLOB_LENGTH.)</span></div>
<div class="line"><a id="l00515" name="l00515"></a><span class="lineno">  515</span><span class="comment"> *</span></div>
<div class="line"><a id="l00516" name="l00516"></a><span class="lineno">  516</span><span class="comment"> * As noted in that concept&#39;s docs, naturally, `S.send_native_handle()` shall yield immediate, non-pipe-hosing</span></div>
<div class="line"><a id="l00517" name="l00517"></a><span class="lineno">  517</span><span class="comment"> * error::Code::S_INVALID_ARGUMENT, if `meta_blob.size() &gt; L`.  This is called overflow and is always enforced.</span></div>
<div class="line"><a id="l00518" name="l00518"></a><span class="lineno">  518</span><span class="comment"> *</span></div>
<div class="line"><a id="l00519" name="l00519"></a><span class="lineno">  519</span><span class="comment"> * Now consider `N = meta_blob.size()` for `R.async_receive_native_handle()`.  This is the size of the target</span></div>
<div class="line"><a id="l00520" name="l00520"></a><span class="lineno">  520</span><span class="comment"> * blob: how many bytes it *can* receive.  How `L` is enforced by `R` is not uniform among this concept&#39;s impls:</span></div>
<div class="line"><a id="l00521" name="l00521"></a><span class="lineno">  521</span><span class="comment"> * rather it depends on the compile-time constant Native_handle_receiver::S_META_BLOB_UNDERFLOW_ALLOWED.</span></div>
<div class="line"><a id="l00522" name="l00522"></a><span class="lineno">  522</span><span class="comment"> *</span></div>
<div class="line"><a id="l00523" name="l00523"></a><span class="lineno">  523</span><span class="comment"> * ### Semantics: `META_BLOB_UNDERFLOW_ALLOWED` is `false` ###</span></div>
<div class="line"><a id="l00524" name="l00524"></a><span class="lineno">  524</span><span class="comment"> * Suppose it is `false` (as is the case for Blob_stream_mq_receiver).  In that case `N &lt; L` is *disallowed*:</span></div>
<div class="line"><a id="l00525" name="l00525"></a><span class="lineno">  525</span><span class="comment"> * `R.async_receive_native_handle()` *shall always* fail with non-pipe-hosing error::Code::S_INVALID_ARGUMENT</span></div>
<div class="line"><a id="l00526" name="l00526"></a><span class="lineno">  526</span><span class="comment"> * for that reason.  Certainly `N` cannot be zero -- not even if the incoming message is expected to</span></div>
<div class="line"><a id="l00527" name="l00527"></a><span class="lineno">  527</span><span class="comment"> * contain only a non-`.null() Native_handle`.</span></div>
<div class="line"><a id="l00528" name="l00528"></a><span class="lineno">  528</span><span class="comment"> *</span></div>
<div class="line"><a id="l00529" name="l00529"></a><span class="lineno">  529</span><span class="comment"> * @note Formally it&#39;s as written.  Informally the rationale for allowing this restriction is that some low-level</span></div>
<div class="line"><a id="l00530" name="l00530"></a><span class="lineno">  530</span><span class="comment"> *       transports have it; and working around it would probably affect performance and is unnatural.</span></div>
<div class="line"><a id="l00531" name="l00531"></a><span class="lineno">  531</span><span class="comment"> *       In particular Persistent_mq_handle::try_receive() (MQ receive) shall immediately fail if a target buffer</span></div>
<div class="line"><a id="l00532" name="l00532"></a><span class="lineno">  532</span><span class="comment"> *       is supplied smaller than Persistent_mq_handle::max_msg_size().  For both POSIX (`man mq_receive`) and</span></div>
<div class="line"><a id="l00533" name="l00533"></a><span class="lineno">  533</span><span class="comment"> *       bipc (`boost::interprocess::message_queue::try_receive()` docs and source code) it is disallowed at the</span></div>
<div class="line"><a id="l00534" name="l00534"></a><span class="lineno">  534</span><span class="comment"> *       low-level API level.</span></div>
<div class="line"><a id="l00535" name="l00535"></a><span class="lineno">  535</span><span class="comment"> *</span></div>
<div class="line"><a id="l00536" name="l00536"></a><span class="lineno">  536</span><span class="comment"> * Thus since `N &gt;= L` is guaranteed before any actual receipt attempt is made, it is *impossible* for</span></div>
<div class="line"><a id="l00537" name="l00537"></a><span class="lineno">  537</span><span class="comment"> * a message to arrive such that its meta-blob&#39;s size would overflow the target blob (buffer) (of size `N`).</span></div>
<div class="line"><a id="l00538" name="l00538"></a><span class="lineno">  538</span><span class="comment"> * Therefore error::Code::S_MESSAGE_SIZE_EXCEEDS_USER_STORAGE shall not be emitted.</span></div>
<div class="line"><a id="l00539" name="l00539"></a><span class="lineno">  539</span><span class="comment"> *</span></div>
<div class="line"><a id="l00540" name="l00540"></a><span class="lineno">  540</span><span class="comment"> * ### Semantics: `META_BLOB_UNDERFLOW_ALLOWED` is `true` ###</span></div>
<div class="line"><a id="l00541" name="l00541"></a><span class="lineno">  541</span><span class="comment"> * Suppose it is `true` (as is the case for Native_socket_stream).  In that case `N &lt; L` is allowed, in the sense</span></div>
<div class="line"><a id="l00542" name="l00542"></a><span class="lineno">  542</span><span class="comment"> * that `R.async_receive_native_handle()` *shall not* fail with non-pipe-hosing error::Code::S_INVALID_ARGUMENT</span></div>
<div class="line"><a id="l00543" name="l00543"></a><span class="lineno">  543</span><span class="comment"> * for that reason.  In particular, in that case, `N` can even be zero: this implies the incoming message *must*</span></div>
<div class="line"><a id="l00544" name="l00544"></a><span class="lineno">  544</span><span class="comment"> * contain a non-`.null() Native_handle` (it is not allowed to send a message with no content at all).</span></div>
<div class="line"><a id="l00545" name="l00545"></a><span class="lineno">  545</span><span class="comment"> * (In the case of degenerate concept Blob_sender, `N` must exceed zero, as it cannot transmit anything but</span></div>
<div class="line"><a id="l00546" name="l00546"></a><span class="lineno">  546</span><span class="comment"> * blobs.)</span></div>
<div class="line"><a id="l00547" name="l00547"></a><span class="lineno">  547</span><span class="comment"> *</span></div>
<div class="line"><a id="l00548" name="l00548"></a><span class="lineno">  548</span><span class="comment"> * However suppose a message has arrived, and its meta-blob&#39;s size -- which cannot exceed `L` -- is larger than</span></div>
<div class="line"><a id="l00549" name="l00549"></a><span class="lineno">  549</span><span class="comment"> * `N`.  I.e., it would *underflow* the user-supplied target buffer (blob).  In that case:</span></div>
<div class="line"><a id="l00550" name="l00550"></a><span class="lineno">  550</span><span class="comment"> *   - async_receive_native_handle() shall emit error::Code::S_MESSAGE_SIZE_EXCEEDS_USER_STORAGE.</span></div>
<div class="line"><a id="l00551" name="l00551"></a><span class="lineno">  551</span><span class="comment"> *   - This error shall be pipe-hosing (further receive attempts will yield the same error).</span></div>
<div class="line"><a id="l00552" name="l00552"></a><span class="lineno">  552</span><span class="comment"> *</span></div>
<div class="line"><a id="l00553" name="l00553"></a><span class="lineno">  553</span><span class="comment"> * Informal tips: Any blob-size error can be completely avoided by always supplying target blob with `N == L`.</span></div>
<div class="line"><a id="l00554" name="l00554"></a><span class="lineno">  554</span><span class="comment"> * (`N &gt; L` will also work but may be considered wasteful, all else being equal.)  In addition this tactic will</span></div>
<div class="line"><a id="l00555" name="l00555"></a><span class="lineno">  555</span><span class="comment"> * ensure the code will generically work with a different Native_handle_receiver impl for which</span></div>
<div class="line"><a id="l00556" name="l00556"></a><span class="lineno">  556</span><span class="comment"> * `S_META_BLOB_UNDERFLOW_ALLOWED == false`.  Alternatively, the user protocol may be such that you simply know</span></div>
<div class="line"><a id="l00557" name="l00557"></a><span class="lineno">  557</span><span class="comment"> * that `S` will never send messages beyond some limit (smaller than `L`), perhaps for particular messages.</span></div>
<div class="line"><a id="l00558" name="l00558"></a><span class="lineno">  558</span><span class="comment"> * In that case `N` can be set to this smaller-than-`L` value.  However -- such code will fail</span></div>
<div class="line"><a id="l00559" name="l00559"></a><span class="lineno">  559</span><span class="comment"> * if the concept impl is later to switched to one with `S_META_BLOB_UNDERFLOW_ALLOWED == true`.  This may or</span></div>
<div class="line"><a id="l00560" name="l00560"></a><span class="lineno">  560</span><span class="comment"> * may not be an issue depending on your future dev plans.</span></div>
<div class="line"><a id="l00561" name="l00561"></a><span class="lineno">  561</span><span class="comment"> *</span></div>
<div class="line"><a id="l00562" name="l00562"></a><span class="lineno">  562</span><span class="comment"> * ### Summary ###</span></div>
<div class="line"><a id="l00563" name="l00563"></a><span class="lineno">  563</span><span class="comment"> * This dichotomy of possible semantics is a conscious choice.  Mode `false` is a necessity: some low-level transports</span></div>
<div class="line"><a id="l00564" name="l00564"></a><span class="lineno">  564</span><span class="comment"> * enforce it, period.  Mode `true` is to support a possible algorithmic desire to allocate smaller-than-`L`</span></div>
<div class="line"><a id="l00565" name="l00565"></a><span class="lineno">  565</span><span class="comment"> * target buffers.  The problem is some low-level transports allow this; but others don&#39;t.  We did not want to</span></div>
<div class="line"><a id="l00566" name="l00566"></a><span class="lineno">  566</span><span class="comment"> * impose one type&#39;s limitations on users of the other type.  Therefore, if your code is agnostic to the type</span></div>
<div class="line"><a id="l00567" name="l00567"></a><span class="lineno">  567</span><span class="comment"> * of transport, then code as-if `S_META_BLOB_UNDERFLOW_ALLOWED == false`.  Otherwise you may code otherwise.</span></div>
<div class="line"><a id="l00568" name="l00568"></a><span class="lineno">  568</span><span class="comment"> *</span></div>
<div class="line"><a id="l00569" name="l00569"></a><span class="lineno">  569</span><span class="comment"> * Rationale: Why no `end_receiving()`, given opposing concept has `*end_sending()`?</span></div>
<div class="line"><a id="l00570" name="l00570"></a><span class="lineno">  570</span><span class="comment"> * ---------------------------------------------------------------------------------</span></div>
<div class="line"><a id="l00571" name="l00571"></a><span class="lineno">  571</span><span class="comment"> * An early version of Native_handle_receiver and Blob_receiver did have an `end_receiving()`.</span></div>
<div class="line"><a id="l00572" name="l00572"></a><span class="lineno">  572</span><span class="comment"> * The idea was it would have 2 effects (plus 1 bonus):</span></div>
<div class="line"><a id="l00573" name="l00573"></a><span class="lineno">  573</span><span class="comment"> *   -# Any ongoing `async_receive_*()`s would be interrupted with in-pipe-hosing error</span></div>
<div class="line"><a id="l00574" name="l00574"></a><span class="lineno">  574</span><span class="comment"> *      error::Code::S_RECEIVES_FINISHED_CANNOT_RECEIVE -- the same one as when receing a graceful-close</span></div>
<div class="line"><a id="l00575" name="l00575"></a><span class="lineno">  575</span><span class="comment"> *      from opposing `*end_sending()`.</span></div>
<div class="line"><a id="l00576" name="l00576"></a><span class="lineno">  576</span><span class="comment"> *   -# There would be no further reading from the low-level transport for any reason.</span></div>
<div class="line"><a id="l00577" name="l00577"></a><span class="lineno">  577</span><span class="comment"> *   -# There was also the *thought*, but not the action, that an impl could inform the *opposing sender* of the</span></div>
<div class="line"><a id="l00578" name="l00578"></a><span class="lineno">  578</span><span class="comment"> *      pipe being closed by the reader.  This would be conceptually similar to SIGPIPE in POSIX.  In practice, of</span></div>
<div class="line"><a id="l00579" name="l00579"></a><span class="lineno">  579</span><span class="comment"> *      the available low-level transports as of this writing, only Native_socket_stream could actually implement it,</span></div>
<div class="line"><a id="l00580" name="l00580"></a><span class="lineno">  580</span><span class="comment"> *      as the otherwise-full-duplex independent pipes do live in this same peer (Unix domain socket), so the out-pipe</span></div>
<div class="line"><a id="l00581" name="l00581"></a><span class="lineno">  581</span><span class="comment"> *      could be used to inform the other guy that *his* out-pipe (our in-pipe) is now pointless.  `Blob_stream_mq_*`</span></div>
<div class="line"><a id="l00582" name="l00582"></a><span class="lineno">  582</span><span class="comment"> *      are fully independent, operating on separate MQ kernel objects, so it was not realistically possible in</span></div>
<div class="line"><a id="l00583" name="l00583"></a><span class="lineno">  583</span><span class="comment"> *      that case.</span></div>
<div class="line"><a id="l00584" name="l00584"></a><span class="lineno">  584</span><span class="comment"> *</span></div>
<div class="line"><a id="l00585" name="l00585"></a><span class="lineno">  585</span><span class="comment"> * In order: (1) is fairly dubious: the local user should know when they&#39;ve stopped receiving and don&#39;t need to</span></div>
<div class="line"><a id="l00586" name="l00586"></a><span class="lineno">  586</span><span class="comment"> * use this mechanism to inform themselves.  (3), as stated, sounded like a possible future improvement, but time</span></div>
<div class="line"><a id="l00587" name="l00587"></a><span class="lineno">  587</span><span class="comment"> * told us it was not going to work out: if only a 2-pipe transport can do it in any case, organizing a concept</span></div>
<div class="line"><a id="l00588" name="l00588"></a><span class="lineno">  588</span><span class="comment"> * around such a thing is just complicated.  If necessary the user can (and we think likely will) just arrange</span></div>
<div class="line"><a id="l00589" name="l00589"></a><span class="lineno">  589</span><span class="comment"> * their own protocol.  So that leaves (2).</span></div>
<div class="line"><a id="l00590" name="l00590"></a><span class="lineno">  590</span><span class="comment"> *</span></div>
<div class="line"><a id="l00591" name="l00591"></a><span class="lineno">  591</span><span class="comment"> * To begin with -- in reality user protocols tend to be designed to not need such measures.  If the reader is no</span></div>
<div class="line"><a id="l00592" name="l00592"></a><span class="lineno">  592</span><span class="comment"> * longer interested, writer will probably know that.  This is not networking after all: it is IPC.</span></div>
<div class="line"><a id="l00593" name="l00593"></a><span class="lineno">  593</span><span class="comment"> * That aside, though, it only makes sense in any case if an impl *chooses* to greedily cache all low-level</span></div>
<div class="line"><a id="l00594" name="l00594"></a><span class="lineno">  594</span><span class="comment"> * in-traffic in user RAM, even while no `async_receive_*()`s are pending to read it.  Early on we actually did do</span></div>
<div class="line"><a id="l00595" name="l00595"></a><span class="lineno">  595</span><span class="comment"> * that; but with the move to `sync_io`-pattern cores, and after contemplating</span></div>
<div class="line"><a id="l00596" name="l00596"></a><span class="lineno">  596</span><span class="comment"> * &quot;Rationale: Why is send-native-handle not asynchronous?&quot; (Native_handle_sender concept doc header),</span></div>
<div class="line"><a id="l00597" name="l00597"></a><span class="lineno">  597</span><span class="comment"> * we got rid of this waste of compute, letting unwanted in-traffic accumulate within a sender peer object</span></div>
<div class="line"><a id="l00598" name="l00598"></a><span class="lineno">  598</span><span class="comment"> * (Native_handle_sender, Blob_sender) only.  So in practice:</span></div>
<div class="line"><a id="l00599" name="l00599"></a><span class="lineno">  599</span><span class="comment"> *</span></div>
<div class="line"><a id="l00600" name="l00600"></a><span class="lineno">  600</span><span class="comment"> * If `end_receiving()` does not signal anything of value ((1) and (3)), and does not actually prevent any</span></div>
<div class="line"><a id="l00601" name="l00601"></a><span class="lineno">  601</span><span class="comment"> * low-level reading that would otherwise occur, then it is a pointless complication.  So that is why we got rid of it.</span></div>
<div class="line"><a id="l00602" name="l00602"></a><span class="lineno">  602</span><span class="comment"> */</span></div>
<div class="line"><a id="l00603" name="l00603"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html">  603</a></span><span class="keyword">class </span><a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a></div>
<div class="line"><a id="l00604" name="l00604"></a><span class="lineno">  604</span>{</div>
<div class="line"><a id="l00605" name="l00605"></a><span class="lineno">  605</span><span class="keyword">public</span>:</div>
<div class="line"><a id="l00606" name="l00606"></a><span class="lineno">  606</span>  <span class="comment">// Constants.</span></div>
<div class="line"><a id="l00607" name="l00607"></a><span class="lineno">  607</span><span class="comment"></span> </div>
<div class="line"><a id="l00608" name="l00608"></a><span class="lineno">  608</span><span class="comment">  /// Shared_name relative-folder fragment (no separators) identifying this resource type.  Equals `_sender`&#39;s.</span></div>
<div class="line"><a id="l00609" name="l00609"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#aa15bb92746ecd8973ed4959ee7606936">  609</a></span><span class="comment"></span>  <span class="keyword">static</span> <span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1util_1_1Shared__name.html">Shared_name</a> <a class="code hl_variable" href="classipc_1_1transport_1_1Native__handle__receiver.html#aa15bb92746ecd8973ed4959ee7606936">S_RESOURCE_TYPE_ID</a>;</div>
<div class="line"><a id="l00610" name="l00610"></a><span class="lineno">  610</span><span class="comment"></span> </div>
<div class="line"><a id="l00611" name="l00611"></a><span class="lineno">  611</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00612" name="l00612"></a><span class="lineno">  612</span><span class="comment">   * If `false` then `meta_blob.size() &gt; receive_meta_blob_max_size()` in PEER-state async_receive_native_handle()</span></div>
<div class="line"><a id="l00613" name="l00613"></a><span class="lineno">  613</span><span class="comment">   * shall yield non-pipe-hosing error::Code::INVALID_ARGUMENT, and it shall never yield</span></div>
<div class="line"><a id="l00614" name="l00614"></a><span class="lineno">  614</span><span class="comment">   * pipe-hosing error::Code::S_MESSAGE_SIZE_EXCEEDS_USER_STORAGE; else the latter may occur, while the former</span></div>
<div class="line"><a id="l00615" name="l00615"></a><span class="lineno">  615</span><span class="comment">   * shall never occur for that reason.</span></div>
<div class="line"><a id="l00616" name="l00616"></a><span class="lineno">  616</span><span class="comment">   *</span></div>
<div class="line"><a id="l00617" name="l00617"></a><span class="lineno">  617</span><span class="comment">   * @see &quot;Blob underflow semantics&quot; in class concept doc header.</span></div>
<div class="line"><a id="l00618" name="l00618"></a><span class="lineno">  618</span><span class="comment">   */</span></div>
<div class="line"><a id="l00619" name="l00619"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#a46b36a6fd79af85829de46b34d3c6849">  619</a></span>  <span class="keyword">static</span> <span class="keyword">constexpr</span> <span class="keywordtype">bool</span> <a class="code hl_variable" href="classipc_1_1transport_1_1Native__handle__receiver.html#a46b36a6fd79af85829de46b34d3c6849">S_META_BLOB_UNDERFLOW_ALLOWED</a> = value;</div>
<div class="line"><a id="l00620" name="l00620"></a><span class="lineno">  620</span> </div>
<div class="line"><a id="l00621" name="l00621"></a><span class="lineno">  621</span>  <span class="comment">// Constructors/destructor.</span></div>
<div class="line"><a id="l00622" name="l00622"></a><span class="lineno">  622</span><span class="comment"></span> </div>
<div class="line"><a id="l00623" name="l00623"></a><span class="lineno">  623</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00624" name="l00624"></a><span class="lineno">  624</span><span class="comment">   * Default ctor: Creates a peer object in NULL (neither connected nor connecting) state.  In this state,</span></div>
<div class="line"><a id="l00625" name="l00625"></a><span class="lineno">  625</span><span class="comment">   * all transmission-related methods (e.g., async_receive_native_handle()) shall return `false` and otherwise no-op</span></div>
<div class="line"><a id="l00626" name="l00626"></a><span class="lineno">  626</span><span class="comment">   * (aside from possible logging).</span></div>
<div class="line"><a id="l00627" name="l00627"></a><span class="lineno">  627</span><span class="comment">   *</span></div>
<div class="line"><a id="l00628" name="l00628"></a><span class="lineno">  628</span><span class="comment">   * All notes from Native_handle_sender() default ctor doc header apply here analogously.  They are helpful so</span></div>
<div class="line"><a id="l00629" name="l00629"></a><span class="lineno">  629</span><span class="comment">   * please read Native_handle_sender() doc header.</span></div>
<div class="line"><a id="l00630" name="l00630"></a><span class="lineno">  630</span><span class="comment">   */</span></div>
<div class="line"><a id="l00631" name="l00631"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#a748df49e5098e922c5974643d7a1bbde">  631</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#a748df49e5098e922c5974643d7a1bbde">Native_handle_receiver</a>();</div>
<div class="line"><a id="l00632" name="l00632"></a><span class="lineno">  632</span><span class="comment"></span> </div>
<div class="line"><a id="l00633" name="l00633"></a><span class="lineno">  633</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00634" name="l00634"></a><span class="lineno">  634</span><span class="comment">   * `sync_io`-core-adopting ctor: Creates a peer object in PEER state by subsuming a `sync_io` core in that state.</span></div>
<div class="line"><a id="l00635" name="l00635"></a><span class="lineno">  635</span><span class="comment">   * That core must be as-if-just-cted (having performed no work and not been configured via `.start_*_ops()`).</span></div>
<div class="line"><a id="l00636" name="l00636"></a><span class="lineno">  636</span><span class="comment">   * That core object becomes as-if default-cted (therefore in NULL state).</span></div>
<div class="line"><a id="l00637" name="l00637"></a><span class="lineno">  637</span><span class="comment">   *</span></div>
<div class="line"><a id="l00638" name="l00638"></a><span class="lineno">  638</span><span class="comment">   * @param sync_io_core_in_peer_state_moved</span></div>
<div class="line"><a id="l00639" name="l00639"></a><span class="lineno">  639</span><span class="comment">   *        See above.</span></div>
<div class="line"><a id="l00640" name="l00640"></a><span class="lineno">  640</span><span class="comment">   */</span></div>
<div class="line"><a id="l00641" name="l00641"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#accd891967ffb57341a26ed0764012713">  641</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#accd891967ffb57341a26ed0764012713">Native_handle_receiver</a>(<a class="code hl_class" href="classipc_1_1transport_1_1sync__io_1_1Native__handle__receiver.html">sync_io::Native_handle_receiver</a>&amp;&amp; sync_io_core_in_peer_state_moved);</div>
<div class="line"><a id="l00642" name="l00642"></a><span class="lineno">  642</span><span class="comment"></span> </div>
<div class="line"><a id="l00643" name="l00643"></a><span class="lineno">  643</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00644" name="l00644"></a><span class="lineno">  644</span><span class="comment">   * Move-constructs from `src`; `src` becomes as-if default-cted (therefore in NULL state).</span></div>
<div class="line"><a id="l00645" name="l00645"></a><span class="lineno">  645</span><span class="comment">   *</span></div>
<div class="line"><a id="l00646" name="l00646"></a><span class="lineno">  646</span><span class="comment">   * @param src</span></div>
<div class="line"><a id="l00647" name="l00647"></a><span class="lineno">  647</span><span class="comment">   *        Source object.  For reasonable uses of `src` after this ctor returns: see default ctor doc header.</span></div>
<div class="line"><a id="l00648" name="l00648"></a><span class="lineno">  648</span><span class="comment">   */</span></div>
<div class="line"><a id="l00649" name="l00649"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#a01de65ed1a7c747e5569e14221b6f9bf">  649</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#a01de65ed1a7c747e5569e14221b6f9bf">Native_handle_receiver</a>(<a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a>&amp;&amp; src);</div>
<div class="line"><a id="l00650" name="l00650"></a><span class="lineno">  650</span><span class="comment"></span> </div>
<div class="line"><a id="l00651" name="l00651"></a><span class="lineno">  651</span><span class="comment">  /// Disallow copying.</span></div>
<div class="line"><a id="l00652" name="l00652"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#afa535558f8e9157d9e95e143376bb6e3">  652</a></span><span class="comment"></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#afa535558f8e9157d9e95e143376bb6e3">Native_handle_receiver</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a>&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00653" name="l00653"></a><span class="lineno">  653</span><span class="comment"></span> </div>
<div class="line"><a id="l00654" name="l00654"></a><span class="lineno">  654</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00655" name="l00655"></a><span class="lineno">  655</span><span class="comment">   * Destroys this peer endpoint which will end the conceptual incoming-direction pipe (in PEER state, and if it&#39;s</span></div>
<div class="line"><a id="l00656" name="l00656"></a><span class="lineno">  656</span><span class="comment">   * still active) and cancels any pending completion handlers by invoking them ASAP with</span></div>
<div class="line"><a id="l00657" name="l00657"></a><span class="lineno">  657</span><span class="comment">   * error::Code::S_OBJECT_SHUTDOWN_ABORTED_COMPLETION_HANDLER.</span></div>
<div class="line"><a id="l00658" name="l00658"></a><span class="lineno">  658</span><span class="comment">   * As of this writing these are the completion handlers that would therefore be called:</span></div>
<div class="line"><a id="l00659" name="l00659"></a><span class="lineno">  659</span><span class="comment">   *   - Any handler passed to async_receive_native_handle() that has not yet been invoked.</span></div>
<div class="line"><a id="l00660" name="l00660"></a><span class="lineno">  660</span><span class="comment">   *     There can be 0 or more of these.</span></div>
<div class="line"><a id="l00661" name="l00661"></a><span class="lineno">  661</span><span class="comment">   *</span></div>
<div class="line"><a id="l00662" name="l00662"></a><span class="lineno">  662</span><span class="comment">   * The pending completion handler(s) (if any) will be called from an unspecified thread that is not the calling</span></div>
<div class="line"><a id="l00663" name="l00663"></a><span class="lineno">  663</span><span class="comment">   * thread.  Any associated captured state for that handler will be freed shortly after the handler returns.</span></div>
<div class="line"><a id="l00664" name="l00664"></a><span class="lineno">  664</span><span class="comment">   *</span></div>
<div class="line"><a id="l00665" name="l00665"></a><span class="lineno">  665</span><span class="comment">   * The rest of the notes in ~Native_handle_sender() apply equally here.</span></div>
<div class="line"><a id="l00666" name="l00666"></a><span class="lineno">  666</span><span class="comment">   *</span></div>
<div class="line"><a id="l00667" name="l00667"></a><span class="lineno">  667</span><span class="comment">   * @see Native_handle_sender::~Native_handle_sender(): sister concept with essentially equal requirements.</span></div>
<div class="line"><a id="l00668" name="l00668"></a><span class="lineno">  668</span><span class="comment">   * @see Native_socket_stream::~Native_socket_stream(): implements concept (also implements just-mentioned sister</span></div>
<div class="line"><a id="l00669" name="l00669"></a><span class="lineno">  669</span><span class="comment">   *      concept).</span></div>
<div class="line"><a id="l00670" name="l00670"></a><span class="lineno">  670</span><span class="comment">   */</span></div>
<div class="line"><a id="l00671" name="l00671"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#ae6d2627aa6ee2216cddbc801a28fa268">  671</a></span>  <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#ae6d2627aa6ee2216cddbc801a28fa268">~Native_handle_receiver</a>();</div>
<div class="line"><a id="l00672" name="l00672"></a><span class="lineno">  672</span> </div>
<div class="line"><a id="l00673" name="l00673"></a><span class="lineno">  673</span>  <span class="comment">// Methods.</span></div>
<div class="line"><a id="l00674" name="l00674"></a><span class="lineno">  674</span><span class="comment"></span> </div>
<div class="line"><a id="l00675" name="l00675"></a><span class="lineno">  675</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00676" name="l00676"></a><span class="lineno">  676</span><span class="comment">   * Move-assigns from `src`; `*this` acts as if destructed; `src` becomes as-if default-cted (therefore in NULL state).</span></div>
<div class="line"><a id="l00677" name="l00677"></a><span class="lineno">  677</span><span class="comment">   * No-op if `&amp;src == this`.</span></div>
<div class="line"><a id="l00678" name="l00678"></a><span class="lineno">  678</span><span class="comment">   *</span></div>
<div class="line"><a id="l00679" name="l00679"></a><span class="lineno">  679</span><span class="comment">   * @see ~Native_handle_receiver().</span></div>
<div class="line"><a id="l00680" name="l00680"></a><span class="lineno">  680</span><span class="comment">   *</span></div>
<div class="line"><a id="l00681" name="l00681"></a><span class="lineno">  681</span><span class="comment">   * @param src</span></div>
<div class="line"><a id="l00682" name="l00682"></a><span class="lineno">  682</span><span class="comment">   *        Source object.  For reasonable uses of `src` after this ctor returns: see default ctor doc header.</span></div>
<div class="line"><a id="l00683" name="l00683"></a><span class="lineno">  683</span><span class="comment">   * @return `*this`.</span></div>
<div class="line"><a id="l00684" name="l00684"></a><span class="lineno">  684</span><span class="comment">   */</span></div>
<div class="line"><a id="l00685" name="l00685"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#a78fbe1f543021b7b5d2ec1be70b83660">  685</a></span>  <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a>&amp; <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#a78fbe1f543021b7b5d2ec1be70b83660">operator=</a>(<a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a>&amp;&amp; src);</div>
<div class="line"><a id="l00686" name="l00686"></a><span class="lineno">  686</span><span class="comment"></span> </div>
<div class="line"><a id="l00687" name="l00687"></a><span class="lineno">  687</span><span class="comment">  /// Disallow copying.</span></div>
<div class="line"><a id="l00688" name="l00688"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#a2a3c7bb6843b8e1c2cabc9ce5ea2f709">  688</a></span><span class="comment"></span>  <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a>&amp; <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#a2a3c7bb6843b8e1c2cabc9ce5ea2f709">operator=</a>(<span class="keyword">const</span> <a class="code hl_class" href="classipc_1_1transport_1_1Native__handle__receiver.html">Native_handle_receiver</a>&amp;) = <span class="keyword">delete</span>;</div>
<div class="line"><a id="l00689" name="l00689"></a><span class="lineno">  689</span><span class="comment"></span> </div>
<div class="line"><a id="l00690" name="l00690"></a><span class="lineno">  690</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00691" name="l00691"></a><span class="lineno">  691</span><span class="comment">   * In PEER state: Returns min `target_meta_blob.size()` such that (1) async_receive_native_handle() shall not fail</span></div>
<div class="line"><a id="l00692" name="l00692"></a><span class="lineno">  692</span><span class="comment">   * with error::Code::S_INVALID_ARGUMENT (only if #S_META_BLOB_UNDERFLOW_ALLOWED is `false`; otherwise not relevant),</span></div>
<div class="line"><a id="l00693" name="l00693"></a><span class="lineno">  693</span><span class="comment">   * and (2) it shall *never* fail with error::Code::S_MESSAGE_SIZE_EXCEEDS_USER_STORAGE.  Please see</span></div>
<div class="line"><a id="l00694" name="l00694"></a><span class="lineno">  694</span><span class="comment">   * &quot;Blob underflow semantics&quot; for explanation of these semantics.</span></div>
<div class="line"><a id="l00695" name="l00695"></a><span class="lineno">  695</span><span class="comment">   *</span></div>
<div class="line"><a id="l00696" name="l00696"></a><span class="lineno">  696</span><span class="comment">   * Always the same value once in PEER state.  The opposing</span></div>
<div class="line"><a id="l00697" name="l00697"></a><span class="lineno">  697</span><span class="comment">   * Blob_sender::send_meta_blob_max_size() shall return the same value (in the opposing object potentially</span></div>
<div class="line"><a id="l00698" name="l00698"></a><span class="lineno">  698</span><span class="comment">   * in a different process).</span></div>
<div class="line"><a id="l00699" name="l00699"></a><span class="lineno">  699</span><span class="comment">   *</span></div>
<div class="line"><a id="l00700" name="l00700"></a><span class="lineno">  700</span><span class="comment">   * If `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns zero; else</span></div>
<div class="line"><a id="l00701" name="l00701"></a><span class="lineno">  701</span><span class="comment">   * a positive value.</span></div>
<div class="line"><a id="l00702" name="l00702"></a><span class="lineno">  702</span><span class="comment">   *</span></div>
<div class="line"><a id="l00703" name="l00703"></a><span class="lineno">  703</span><span class="comment">   * @return See above.</span></div>
<div class="line"><a id="l00704" name="l00704"></a><span class="lineno">  704</span><span class="comment">   */</span></div>
<div class="line"><a id="l00705" name="l00705"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#ae9dd851d38af7c3715a64d0b111ba721">  705</a></span>  <span class="keywordtype">size_t</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#ae9dd851d38af7c3715a64d0b111ba721">receive_meta_blob_max_size</a>() <span class="keyword">const</span>;</div>
<div class="line"><a id="l00706" name="l00706"></a><span class="lineno">  706</span><span class="comment"></span> </div>
<div class="line"><a id="l00707" name="l00707"></a><span class="lineno">  707</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00708" name="l00708"></a><span class="lineno">  708</span><span class="comment">   * In PEER state: Asynchronously awaits one discrete message -- as sent by the opposing peer via</span></div>
<div class="line"><a id="l00709" name="l00709"></a><span class="lineno">  709</span><span class="comment">   * Native_handle_sender::send_native_handle() or `&quot;Native_handle_sender::*end_sending()&quot;` -- and</span></div>
<div class="line"><a id="l00710" name="l00710"></a><span class="lineno">  710</span><span class="comment">   * receives it into the given target locations, reliably and in-order.  The message is, therefore, one of the</span></div>
<div class="line"><a id="l00711" name="l00711"></a><span class="lineno">  711</span><span class="comment">   * following:</span></div>
<div class="line"><a id="l00712" name="l00712"></a><span class="lineno">  712</span><span class="comment">   *   - A binary blob; a native handle; or both.  This is indicated by `on_done_func(Error_code(), N)`.</span></div>
<div class="line"><a id="l00713" name="l00713"></a><span class="lineno">  713</span><span class="comment">   *     The falsy code indicates success; `N &lt;= target_meta_blob.size()` indicates the number of bytes received into</span></div>
<div class="line"><a id="l00714" name="l00714"></a><span class="lineno">  714</span><span class="comment">   *     `target_meta_blob.data()` (zero means no blob was sent in the message).  `*target_hndl` is set</span></div>
<div class="line"><a id="l00715" name="l00715"></a><span class="lineno">  715</span><span class="comment">   *     (`target_hndl-&gt;null() == true` means no handle was sent in the message).</span></div>
<div class="line"><a id="l00716" name="l00716"></a><span class="lineno">  716</span><span class="comment">   *   - Graceful-close.  This is indicated by `on_done_func(error::code::S_RECEIVES_FINISHED_CANNOT_RECEIVE, 0)`;</span></div>
<div class="line"><a id="l00717" name="l00717"></a><span class="lineno">  717</span><span class="comment">   *     neither the target blob nor target native handle are touched.</span></div>
<div class="line"><a id="l00718" name="l00718"></a><span class="lineno">  718</span><span class="comment">   *</span></div>
<div class="line"><a id="l00719" name="l00719"></a><span class="lineno">  719</span><span class="comment">   * If `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns `false` immediately</span></div>
<div class="line"><a id="l00720" name="l00720"></a><span class="lineno">  720</span><span class="comment">   * instead and otherwise no-ops (logging aside).</span></div>
<div class="line"><a id="l00721" name="l00721"></a><span class="lineno">  721</span><span class="comment">   *</span></div>
<div class="line"><a id="l00722" name="l00722"></a><span class="lineno">  722</span><span class="comment">   * ### Blob copying behavior; synchronicity/blockingness guarantees ###</span></div>
<div class="line"><a id="l00723" name="l00723"></a><span class="lineno">  723</span><span class="comment">   * `*target_hndl` and the area described by `target_meta_blob` must both remain valid until `on_done_func()`</span></div>
<div class="line"><a id="l00724" name="l00724"></a><span class="lineno">  724</span><span class="comment">   * executes.  The method itself shall be non-blocking.</span></div>
<div class="line"><a id="l00725" name="l00725"></a><span class="lineno">  725</span><span class="comment">   *</span></div>
<div class="line"><a id="l00726" name="l00726"></a><span class="lineno">  726</span><span class="comment">   * The implementation shall, informally, strive to *not* copy the received blob (if any) into</span></div>
<div class="line"><a id="l00727" name="l00727"></a><span class="lineno">  727</span><span class="comment">   * `target_meta_blob.data()...` except from the low-level transport mechanism.  That is: it shall strive to not</span></div>
<div class="line"><a id="l00728" name="l00728"></a><span class="lineno">  728</span><span class="comment">   * store the blob data in some internal buffer before ending up in `target_meta_blob.data()...`.</span></div>
<div class="line"><a id="l00729" name="l00729"></a><span class="lineno">  729</span><span class="comment">   *</span></div>
<div class="line"><a id="l00730" name="l00730"></a><span class="lineno">  730</span><span class="comment">   * ### Error semantics ###</span></div>
<div class="line"><a id="l00731" name="l00731"></a><span class="lineno">  731</span><span class="comment">   * An #Error_code is generated and passed as the 1st arg to `on_done_func()`.</span></div>
<div class="line"><a id="l00732" name="l00732"></a><span class="lineno">  732</span><span class="comment">   * A falsy one indicates success.  A truthy one indicates failure; but in particular:</span></div>
<div class="line"><a id="l00733" name="l00733"></a><span class="lineno">  733</span><span class="comment">   *   - error::Code::S_OBJECT_SHUTDOWN_ABORTED_COMPLETION_HANDLER (destructor called, canceling all pending ops;</span></div>
<div class="line"><a id="l00734" name="l00734"></a><span class="lineno">  734</span><span class="comment">   *     spiritually identical to `boost::asio::error::operation_aborted`);</span></div>
<div class="line"><a id="l00735" name="l00735"></a><span class="lineno">  735</span><span class="comment">   *   - only if #S_META_BLOB_UNDERFLOW_ALLOWED is `true`:</span></div>
<div class="line"><a id="l00736" name="l00736"></a><span class="lineno">  736</span><span class="comment">   *     - error::Code::S_MESSAGE_SIZE_EXCEEDS_USER_STORAGE (opposing peer has sent a message with a meta-blob exceeding</span></div>
<div class="line"><a id="l00737" name="l00737"></a><span class="lineno">  737</span><span class="comment">   *       `target_meta_blob.size()` in length; in particular one can give an empty buffer if no meta-blob expected);</span></div>
<div class="line"><a id="l00738" name="l00738"></a><span class="lineno">  738</span><span class="comment">   *   - error::Code::S_RECEIVES_FINISHED_CANNOT_RECEIVE (peer gracefully closed pipe via `*end_sending()`);</span></div>
<div class="line"><a id="l00739" name="l00739"></a><span class="lineno">  739</span><span class="comment">   *   - error::Code::S_RECEIVER_IDLE_TIMEOUT (idle timeout: see idle_timer_run());</span></div>
<div class="line"><a id="l00740" name="l00740"></a><span class="lineno">  740</span><span class="comment">   *   - other arbitrary codes are possible.</span></div>
<div class="line"><a id="l00741" name="l00741"></a><span class="lineno">  741</span><span class="comment">   *   - No would-block-like error condition shall be emitted.</span></div>
<div class="line"><a id="l00742" name="l00742"></a><span class="lineno">  742</span><span class="comment">   *</span></div>
<div class="line"><a id="l00743" name="l00743"></a><span class="lineno">  743</span><span class="comment">   * A non-success on-done invocation means the incoming pipe is hosed.  (It is recommended they cease to use the pipe</span></div>
<div class="line"><a id="l00744" name="l00744"></a><span class="lineno">  744</span><span class="comment">   * and invoke the destructor to free resources.)  If such a non-success code is emitted, the same one shall be emitted</span></div>
<div class="line"><a id="l00745" name="l00745"></a><span class="lineno">  745</span><span class="comment">   * by all further async_receive_native_handle() calls on `*this`.  Key exception:</span></div>
<div class="line"><a id="l00746" name="l00746"></a><span class="lineno">  746</span><span class="comment">   *   - error::Code::S_INVALID_ARGUMENT:</span></div>
<div class="line"><a id="l00747" name="l00747"></a><span class="lineno">  747</span><span class="comment">   *     - This refers to an invalid argument to *this* method invocation.</span></div>
<div class="line"><a id="l00748" name="l00748"></a><span class="lineno">  748</span><span class="comment">   *       - If and only if #S_META_BLOB_UNDERFLOW_ALLOWED is `false`: A length floor on the target blob is imposed.</span></div>
<div class="line"><a id="l00749" name="l00749"></a><span class="lineno">  749</span><span class="comment">   *         Hence if `target_meta_blob.size() &lt; receive_meta_blob_max_size()` then `S_INVALID_ARGUMENT` is emitted.</span></div>
<div class="line"><a id="l00750" name="l00750"></a><span class="lineno">  750</span><span class="comment">   *     - This shall *not* hose the pipe.  Subsequent async-receives may be attempted with reasonable hope of</span></div>
<div class="line"><a id="l00751" name="l00751"></a><span class="lineno">  751</span><span class="comment">   *       success.</span></div>
<div class="line"><a id="l00752" name="l00752"></a><span class="lineno">  752</span><span class="comment">   *     - At the impl&#39;s discretion, other conditions *may* lead to `S_INVALID_ARGUMENT`.  If so they must</span></div>
<div class="line"><a id="l00753" name="l00753"></a><span class="lineno">  753</span><span class="comment">   *       be documented.</span></div>
<div class="line"><a id="l00754" name="l00754"></a><span class="lineno">  754</span><span class="comment">   *</span></div>
<div class="line"><a id="l00755" name="l00755"></a><span class="lineno">  755</span><span class="comment">   * ### Thread safety ###</span></div>
<div class="line"><a id="l00756" name="l00756"></a><span class="lineno">  756</span><span class="comment">   * You may call this either from any thread including the unspecified thread running within another call&#39;s</span></div>
<div class="line"><a id="l00757" name="l00757"></a><span class="lineno">  757</span><span class="comment">   * `on_done_func()`.  It is *not* required to be safe to call concurrently with any Native_handle_receiver API,</span></div>
<div class="line"><a id="l00758" name="l00758"></a><span class="lineno">  758</span><span class="comment">   * including this one and the destructor, invoked on `*this`.</span></div>
<div class="line"><a id="l00759" name="l00759"></a><span class="lineno">  759</span><span class="comment">   *</span></div>
<div class="line"><a id="l00760" name="l00760"></a><span class="lineno">  760</span><span class="comment">   * @tparam Task_err_sz</span></div>
<div class="line"><a id="l00761" name="l00761"></a><span class="lineno">  761</span><span class="comment">   *         A functor type with signature identical to `flow::async::Task_asio_err_sz`.</span></div>
<div class="line"><a id="l00762" name="l00762"></a><span class="lineno">  762</span><span class="comment">   * @param target_hndl</span></div>
<div class="line"><a id="l00763" name="l00763"></a><span class="lineno">  763</span><span class="comment">   *        `*target_hndl` shall be set by the time `on_done_func()` is executed with a falsy code.  See above.</span></div>
<div class="line"><a id="l00764" name="l00764"></a><span class="lineno">  764</span><span class="comment">   * @param target_meta_blob</span></div>
<div class="line"><a id="l00765" name="l00765"></a><span class="lineno">  765</span><span class="comment">   *        `target_meta_blob.data()...` shall be written to by the time `on_done_func()` is executed with a falsy</span></div>
<div class="line"><a id="l00766" name="l00766"></a><span class="lineno">  766</span><span class="comment">   *        code, bytes numbering `N`, where `N` is passed to that callback.  `N` shall not exceed</span></div>
<div class="line"><a id="l00767" name="l00767"></a><span class="lineno">  767</span><span class="comment">   *        `target_meta_blob.size()`.  See above.</span></div>
<div class="line"><a id="l00768" name="l00768"></a><span class="lineno">  768</span><span class="comment">   * @param on_done_func</span></div>
<div class="line"><a id="l00769" name="l00769"></a><span class="lineno">  769</span><span class="comment">   *        See above.  This shall be invoked from an unspecified thread that is not the calling thread.</span></div>
<div class="line"><a id="l00770" name="l00770"></a><span class="lineno">  770</span><span class="comment">   * @return `false` if `*this` is not in PEER (connected, transmitting) state;</span></div>
<div class="line"><a id="l00771" name="l00771"></a><span class="lineno">  771</span><span class="comment">   *         otherwise `true`.</span></div>
<div class="line"><a id="l00772" name="l00772"></a><span class="lineno">  772</span><span class="comment">   */</span></div>
<div class="line"><a id="l00773" name="l00773"></a><span class="lineno">  773</span>  <span class="keyword">template</span>&lt;<span class="keyword">typename</span> Task_err_sz&gt;</div>
<div class="line"><a id="l00774" name="l00774"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#ae4ac1685f00467a6516f9f24f5d8a280">  774</a></span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#ae4ac1685f00467a6516f9f24f5d8a280">async_receive_native_handle</a>(<a class="code hl_struct" href="structipc_1_1util_1_1Native__handle.html">Native_handle</a>* target_hndl,</div>
<div class="line"><a id="l00775" name="l00775"></a><span class="lineno">  775</span>                                   <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">util::Blob_mutable</a>&amp; target_meta_blob,</div>
<div class="line"><a id="l00776" name="l00776"></a><span class="lineno">  776</span>                                   Task_err_sz&amp;&amp; on_done_func);</div>
<div class="line"><a id="l00777" name="l00777"></a><span class="lineno">  777</span><span class="comment"></span> </div>
<div class="line"><a id="l00778" name="l00778"></a><span class="lineno">  778</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00779" name="l00779"></a><span class="lineno">  779</span><span class="comment">   * In PEER state: Irreversibly enables a conceptual idle timer whose potential side effect is, once at least</span></div>
<div class="line"><a id="l00780" name="l00780"></a><span class="lineno">  780</span><span class="comment">   * the specified time has passed since the last received low-level traffic (or this call, whichever most</span></div>
<div class="line"><a id="l00781" name="l00781"></a><span class="lineno">  781</span><span class="comment">   * recently occurred), to emit the pipe-hosing error error::Code::S_RECEIVER_IDLE_TIMEOUT.  The implementation</span></div>
<div class="line"><a id="l00782" name="l00782"></a><span class="lineno">  782</span><span class="comment">   * shall guarantee the observer idle timeout is at least the provided value but may exceed this value for</span></div>
<div class="line"><a id="l00783" name="l00783"></a><span class="lineno">  783</span><span class="comment">   * internal reasons, as long as it&#39;s by a less than human-perceptible period (roughly speaking -- milliseconds,</span></div>
<div class="line"><a id="l00784" name="l00784"></a><span class="lineno">  784</span><span class="comment">   * not seconds).</span></div>
<div class="line"><a id="l00785" name="l00785"></a><span class="lineno">  785</span><span class="comment">   *</span></div>
<div class="line"><a id="l00786" name="l00786"></a><span class="lineno">  786</span><span class="comment">   * If `*this` is not in PEER state (in particular if it is default-cted or moved-from), returns `false` immediately</span></div>
<div class="line"><a id="l00787" name="l00787"></a><span class="lineno">  787</span><span class="comment">   * instead and otherwise no-ops (logging aside).  If idle_timer_run() has already been called successfuly,</span></div>
<div class="line"><a id="l00788" name="l00788"></a><span class="lineno">  788</span><span class="comment">   * subsequently it will return `false` and no-op (logging aside).</span></div>
<div class="line"><a id="l00789" name="l00789"></a><span class="lineno">  789</span><span class="comment">   *</span></div>
<div class="line"><a id="l00790" name="l00790"></a><span class="lineno">  790</span><span class="comment">   * ### Important: Relationship between idle_timer_run() and async_receive_native_handle() ###</span></div>
<div class="line"><a id="l00791" name="l00791"></a><span class="lineno">  791</span><span class="comment">   * idle_timer_run() is optional: if you have not called it, then the following does not apply.  If you *have* called</span></div>
<div class="line"><a id="l00792" name="l00792"></a><span class="lineno">  792</span><span class="comment">   * it:</span></div>
<div class="line"><a id="l00793" name="l00793"></a><span class="lineno">  793</span><span class="comment">   *</span></div>
<div class="line"><a id="l00794" name="l00794"></a><span class="lineno">  794</span><span class="comment">   * It will work usefully if and only if subsequently an async_receive_native_handle() is oustanding at least</span></div>
<div class="line"><a id="l00795" name="l00795"></a><span class="lineno">  795</span><span class="comment">   * once each `timeout`.  Informally this means it&#39;s best to immediately issue async_receive_native_handle() --</span></div>
<div class="line"><a id="l00796" name="l00796"></a><span class="lineno">  796</span><span class="comment">   * unless one is already oustanding -- and then as soon as that completes (sans error) issue at least one more;</span></div>
<div class="line"><a id="l00797" name="l00797"></a><span class="lineno">  797</span><span class="comment">   * and so on.  Why?  What are we talking about?  Simple: async_receive_native_handle() impl is *not* required</span></div>
<div class="line"><a id="l00798" name="l00798"></a><span class="lineno">  798</span><span class="comment">   * to read any more data from the low-level transport than is sufficient to satisfy the current</span></div>
<div class="line"><a id="l00799" name="l00799"></a><span class="lineno">  799</span><span class="comment">   * async_receive_native_handle() deficit.  (If it were required to do so, it would&#39;ve been required to store copies</span></div>
<div class="line"><a id="l00800" name="l00800"></a><span class="lineno">  800</span><span class="comment">   * of incoming meta-blobs when there&#39;s no user-request deficit; we&#39;ve consciously avoided unnecessary copying.)</span></div>
<div class="line"><a id="l00801" name="l00801"></a><span class="lineno">  801</span><span class="comment">   * So while there&#39;s no async_receive_native_handle() outstanding, `*this` will be considered idle; and once</span></div>
<div class="line"><a id="l00802" name="l00802"></a><span class="lineno">  802</span><span class="comment">   * that continues long enough for `timeout` to be exceeded, the idle timer will hose the in-pipe.</span></div>
<div class="line"><a id="l00803" name="l00803"></a><span class="lineno">  803</span><span class="comment">   *</span></div>
<div class="line"><a id="l00804" name="l00804"></a><span class="lineno">  804</span><span class="comment">   * So: If you plan to use idle_timer_run(), then you need to be ~always async-receiving.  Otherwise you&#39;ll risk</span></div>
<div class="line"><a id="l00805" name="l00805"></a><span class="lineno">  805</span><span class="comment">   * hitting idle-timeout, even as the other side diligently sends stuff (`auto_ping()` or otherwise).</span></div>
<div class="line"><a id="l00806" name="l00806"></a><span class="lineno">  806</span><span class="comment">   *</span></div>
<div class="line"><a id="l00807" name="l00807"></a><span class="lineno">  807</span><span class="comment">   * ### Error semantics ###</span></div>
<div class="line"><a id="l00808" name="l00808"></a><span class="lineno">  808</span><span class="comment">   * If and only if the timeout does occur down the line, the aforementioned error will be emitted via</span></div>
<div class="line"><a id="l00809" name="l00809"></a><span class="lineno">  809</span><span class="comment">   * async_receive_native_handle() (or similar) handler.  It shall be treated as the reason to hose the pipe</span></div>
<div class="line"><a id="l00810" name="l00810"></a><span class="lineno">  810</span><span class="comment">   * (assuming it was not hosed by something else earlier).</span></div>
<div class="line"><a id="l00811" name="l00811"></a><span class="lineno">  811</span><span class="comment">   *</span></div>
<div class="line"><a id="l00812" name="l00812"></a><span class="lineno">  812</span><span class="comment">   * ### Thread safety ###</span></div>
<div class="line"><a id="l00813" name="l00813"></a><span class="lineno">  813</span><span class="comment">   * You may call this either from any thread including the unspecified thread running within another call&#39;s</span></div>
<div class="line"><a id="l00814" name="l00814"></a><span class="lineno">  814</span><span class="comment">   * `on_done_func()`.  It is *not* required to be safe to call concurrently with any API, including this one</span></div>
<div class="line"><a id="l00815" name="l00815"></a><span class="lineno">  815</span><span class="comment">   * and the destructor, invoked on `*this`.</span></div>
<div class="line"><a id="l00816" name="l00816"></a><span class="lineno">  816</span><span class="comment">   *</span></div>
<div class="line"><a id="l00817" name="l00817"></a><span class="lineno">  817</span><span class="comment">   * ### Suggested use ###</span></div>
<div class="line"><a id="l00818" name="l00818"></a><span class="lineno">  818</span><span class="comment">   * Informally: There are roughly two approaches to using idle_timer_run().</span></div>
<div class="line"><a id="l00819" name="l00819"></a><span class="lineno">  819</span><span class="comment">   *</span></div>
<div class="line"><a id="l00820" name="l00820"></a><span class="lineno">  820</span><span class="comment">   * Firstly it can be used to gauge the state of the opposing process; if no auto-pings are arriving regularly,</span></div>
<div class="line"><a id="l00821" name="l00821"></a><span class="lineno">  821</span><span class="comment">   * then the opposing Native_handle_sender (or similar) must be zombified or overloaded.  To use it in this</span></div>
<div class="line"><a id="l00822" name="l00822"></a><span class="lineno">  822</span><span class="comment">   * capacity, typically one must use Native_handle_sender::auto_ping() (or similar) on the opposing side.</span></div>
<div class="line"><a id="l00823" name="l00823"></a><span class="lineno">  823</span><span class="comment">   * Typically one would then leave `timeout` at its suggested default value.</span></div>
<div class="line"><a id="l00824" name="l00824"></a><span class="lineno">  824</span><span class="comment">   *</span></div>
<div class="line"><a id="l00825" name="l00825"></a><span class="lineno">  825</span><span class="comment">   * Secondly it can be used to more generally ensure some application algorithm on the opposing side (presumably</span></div>
<div class="line"><a id="l00826" name="l00826"></a><span class="lineno">  826</span><span class="comment">   * cooperating with the algorithm on the local side) is sending messages with expected frequency.</span></div>
<div class="line"><a id="l00827" name="l00827"></a><span class="lineno">  827</span><span class="comment">   * That is, one would not use `auto_ping()` but rather send their own messages in a way that makes sense for</span></div>
<div class="line"><a id="l00828" name="l00828"></a><span class="lineno">  828</span><span class="comment">   * the applications&#39; algorithm.</span></div>
<div class="line"><a id="l00829" name="l00829"></a><span class="lineno">  829</span><span class="comment">   *</span></div>
<div class="line"><a id="l00830" name="l00830"></a><span class="lineno">  830</span><span class="comment">   * @param timeout</span></div>
<div class="line"><a id="l00831" name="l00831"></a><span class="lineno">  831</span><span class="comment">   *        The idle timeout to observe.</span></div>
<div class="line"><a id="l00832" name="l00832"></a><span class="lineno">  832</span><span class="comment">   *        The optional default is chosen by the impl to most reasonably work with the opposing `auto_ping()`</span></div>
<div class="line"><a id="l00833" name="l00833"></a><span class="lineno">  833</span><span class="comment">   *        to detect a zombified/overloaded peer.</span></div>
<div class="line"><a id="l00834" name="l00834"></a><span class="lineno">  834</span><span class="comment">   * @return `false` if `*this` is not in PEER (connected, transmitting) state, or if already called successfully</span></div>
<div class="line"><a id="l00835" name="l00835"></a><span class="lineno">  835</span><span class="comment">   *         in `PEER` state; otherwise `true`.</span></div>
<div class="line"><a id="l00836" name="l00836"></a><span class="lineno">  836</span><span class="comment">   */</span></div>
<div class="line"><a id="l00837" name="l00837"></a><span class="lineno"><a class="line" href="classipc_1_1transport_1_1Native__handle__receiver.html#a174ee15818a8bda361bdc40f094faac9">  837</a></span>  <span class="keywordtype">bool</span> <a class="code hl_function" href="classipc_1_1transport_1_1Native__handle__receiver.html#a174ee15818a8bda361bdc40f094faac9">idle_timer_run</a>(<a class="code hl_typedef" href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">util::Fine_duration</a> timeout = default_value);</div>
<div class="line"><a id="l00838" name="l00838"></a><span class="lineno">  838</span>}; <span class="comment">// class Native_handle_receiver</span></div>
<div class="line"><a id="l00839" name="l00839"></a><span class="lineno">  839</span> </div>
<div class="line"><a id="l00840" name="l00840"></a><span class="lineno">  840</span>} <span class="comment">// namespace ipc::transport</span></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html">ipc::transport::Native_handle_receiver</a></div><div class="ttdoc">A documentation-only concept defining the behavior of an object capable of reliably/in-order receivin...</div><div class="ttdef"><b>Definition:</b> <a href="native__handle__transport_8hpp_source.html#l00603">native_handle_transport.hpp:604</a></div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_a01de65ed1a7c747e5569e14221b6f9bf"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#a01de65ed1a7c747e5569e14221b6f9bf">ipc::transport::Native_handle_receiver::Native_handle_receiver</a></div><div class="ttdeci">Native_handle_receiver(Native_handle_receiver &amp;&amp;src)</div><div class="ttdoc">Move-constructs from src; src becomes as-if default-cted (therefore in NULL state).</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_a174ee15818a8bda361bdc40f094faac9"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#a174ee15818a8bda361bdc40f094faac9">ipc::transport::Native_handle_receiver::idle_timer_run</a></div><div class="ttdeci">bool idle_timer_run(util::Fine_duration timeout=default_value)</div><div class="ttdoc">In PEER state: Irreversibly enables a conceptual idle timer whose potential side effect is,...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_a2a3c7bb6843b8e1c2cabc9ce5ea2f709"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#a2a3c7bb6843b8e1c2cabc9ce5ea2f709">ipc::transport::Native_handle_receiver::operator=</a></div><div class="ttdeci">Native_handle_receiver &amp; operator=(const Native_handle_receiver &amp;)=delete</div><div class="ttdoc">Disallow copying.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_a46b36a6fd79af85829de46b34d3c6849"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#a46b36a6fd79af85829de46b34d3c6849">ipc::transport::Native_handle_receiver::S_META_BLOB_UNDERFLOW_ALLOWED</a></div><div class="ttdeci">static constexpr bool S_META_BLOB_UNDERFLOW_ALLOWED</div><div class="ttdoc">If false then meta_blob.size() &gt; receive_meta_blob_max_size() in PEER-state async_receive_native_hand...</div><div class="ttdef"><b>Definition:</b> <a href="native__handle__transport_8hpp_source.html#l00619">native_handle_transport.hpp:619</a></div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_a748df49e5098e922c5974643d7a1bbde"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#a748df49e5098e922c5974643d7a1bbde">ipc::transport::Native_handle_receiver::Native_handle_receiver</a></div><div class="ttdeci">Native_handle_receiver()</div><div class="ttdoc">Default ctor: Creates a peer object in NULL (neither connected nor connecting) state.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_a78fbe1f543021b7b5d2ec1be70b83660"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#a78fbe1f543021b7b5d2ec1be70b83660">ipc::transport::Native_handle_receiver::operator=</a></div><div class="ttdeci">Native_handle_receiver &amp; operator=(Native_handle_receiver &amp;&amp;src)</div><div class="ttdoc">Move-assigns from src; *this acts as if destructed; src becomes as-if default-cted (therefore in NULL...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_aa15bb92746ecd8973ed4959ee7606936"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#aa15bb92746ecd8973ed4959ee7606936">ipc::transport::Native_handle_receiver::S_RESOURCE_TYPE_ID</a></div><div class="ttdeci">static const Shared_name S_RESOURCE_TYPE_ID</div><div class="ttdoc">Shared_name relative-folder fragment (no separators) identifying this resource type....</div><div class="ttdef"><b>Definition:</b> <a href="native__handle__transport_8hpp_source.html#l00609">native_handle_transport.hpp:609</a></div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_accd891967ffb57341a26ed0764012713"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#accd891967ffb57341a26ed0764012713">ipc::transport::Native_handle_receiver::Native_handle_receiver</a></div><div class="ttdeci">Native_handle_receiver(sync_io::Native_handle_receiver &amp;&amp;sync_io_core_in_peer_state_moved)</div><div class="ttdoc">sync_io-core-adopting ctor: Creates a peer object in PEER state by subsuming a sync_io core in that s...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_ae4ac1685f00467a6516f9f24f5d8a280"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#ae4ac1685f00467a6516f9f24f5d8a280">ipc::transport::Native_handle_receiver::async_receive_native_handle</a></div><div class="ttdeci">bool async_receive_native_handle(Native_handle *target_hndl, const util::Blob_mutable &amp;target_meta_blob, Task_err_sz &amp;&amp;on_done_func)</div><div class="ttdoc">In PEER state: Asynchronously awaits one discrete message – as sent by the opposing peer via Native_h...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_ae6d2627aa6ee2216cddbc801a28fa268"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#ae6d2627aa6ee2216cddbc801a28fa268">ipc::transport::Native_handle_receiver::~Native_handle_receiver</a></div><div class="ttdeci">~Native_handle_receiver()</div><div class="ttdoc">Destroys this peer endpoint which will end the conceptual incoming-direction pipe (in PEER state,...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_ae9dd851d38af7c3715a64d0b111ba721"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#ae9dd851d38af7c3715a64d0b111ba721">ipc::transport::Native_handle_receiver::receive_meta_blob_max_size</a></div><div class="ttdeci">size_t receive_meta_blob_max_size() const</div><div class="ttdoc">In PEER state: Returns min target_meta_blob.size() such that (1) async_receive_native_handle() shall ...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__receiver_html_afa535558f8e9157d9e95e143376bb6e3"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__receiver.html#afa535558f8e9157d9e95e143376bb6e3">ipc::transport::Native_handle_receiver::Native_handle_receiver</a></div><div class="ttdeci">Native_handle_receiver(const Native_handle_receiver &amp;)=delete</div><div class="ttdoc">Disallow copying.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html">ipc::transport::Native_handle_sender</a></div><div class="ttdoc">A documentation-only concept defining the behavior of an object capable of reliably/in-order sending ...</div><div class="ttdef"><b>Definition:</b> <a href="native__handle__transport_8hpp_source.html#l00159">native_handle_transport.hpp:160</a></div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a4348f5448609ef83c53a161e472f85d5"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a4348f5448609ef83c53a161e472f85d5">ipc::transport::Native_handle_sender::Native_handle_sender</a></div><div class="ttdeci">Native_handle_sender(Native_handle_sender &amp;&amp;src)</div><div class="ttdoc">Move-constructs from src; src becomes as-if default-cted (therefore in NULL state).</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a4c92fe4e43ddf819a2c767cc53cbe477"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a4c92fe4e43ddf819a2c767cc53cbe477">ipc::transport::Native_handle_sender::async_end_sending</a></div><div class="ttdeci">bool async_end_sending(Task_err &amp;&amp;on_done_func)</div><div class="ttdoc">Equivalent to send_native_handle() but sends a graceful-close message instead of the usual payload; t...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a531e4ea9d23cbcb1c456b51b5fa2dca1"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a531e4ea9d23cbcb1c456b51b5fa2dca1">ipc::transport::Native_handle_sender::Native_handle_sender</a></div><div class="ttdeci">Native_handle_sender(const Native_handle_sender &amp;)=delete</div><div class="ttdoc">Disallow copying.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a616a05a623410acde1fc225cbc22f03f"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a616a05a623410acde1fc225cbc22f03f">ipc::transport::Native_handle_sender::Native_handle_sender</a></div><div class="ttdeci">Native_handle_sender(sync_io::Native_handle_sender &amp;&amp;sync_io_core_in_peer_state_moved)</div><div class="ttdoc">sync_io-core-adopting ctor: Creates a peer object in PEER state by subsuming a sync_io core in that s...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a74452bf96477a7b971e187c67703e8d5"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a74452bf96477a7b971e187c67703e8d5">ipc::transport::Native_handle_sender::send_meta_blob_max_size</a></div><div class="ttdeci">size_t send_meta_blob_max_size() const</div><div class="ttdoc">In PEER state: Returns max meta_blob.size() such that send_native_handle() shall not fail due to too-...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a7de1a7f689cfdd926580cf92131896bb"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a7de1a7f689cfdd926580cf92131896bb">ipc::transport::Native_handle_sender::operator=</a></div><div class="ttdeci">Native_handle_sender &amp; operator=(Native_handle_sender &amp;&amp;src)</div><div class="ttdoc">Move-assigns from src; *this acts as if destructed; src becomes as-if default-cted (therefore in NULL...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a840003f2f91ef73f319e0e6b5e7ab435"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a840003f2f91ef73f319e0e6b5e7ab435">ipc::transport::Native_handle_sender::S_RESOURCE_TYPE_ID</a></div><div class="ttdeci">static const Shared_name S_RESOURCE_TYPE_ID</div><div class="ttdoc">Shared_name relative-folder fragment (no separators) identifying this resource type....</div><div class="ttdef"><b>Definition:</b> <a href="native__handle__transport_8hpp_source.html#l00165">native_handle_transport.hpp:165</a></div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a8a2f1282c18faec36aabf29c99b87054"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a8a2f1282c18faec36aabf29c99b87054">ipc::transport::Native_handle_sender::auto_ping</a></div><div class="ttdeci">bool auto_ping(util::Fine_duration period=default_value)</div><div class="ttdoc">In PEER state: Irreversibly enables periodic auto-pinging of opposing receiver with low-level message...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_a9a784cf71488184323a79695d45adf2e"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#a9a784cf71488184323a79695d45adf2e">ipc::transport::Native_handle_sender::operator=</a></div><div class="ttdeci">Native_handle_sender &amp; operator=(const Native_handle_sender &amp;)=delete</div><div class="ttdoc">Disallow copying.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_aa2354a74bc6cdff9389d0b7b642fbadd"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#aa2354a74bc6cdff9389d0b7b642fbadd">ipc::transport::Native_handle_sender::~Native_handle_sender</a></div><div class="ttdeci">~Native_handle_sender()</div><div class="ttdoc">Destroys this peer endpoint which will end the conceptual outgoing-direction pipe (in PEER state,...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_aa3c2953f7f8a48b8a0cbf49652fb6d41"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#aa3c2953f7f8a48b8a0cbf49652fb6d41">ipc::transport::Native_handle_sender::end_sending</a></div><div class="ttdeci">bool end_sending()</div><div class="ttdoc">Equivalent to async_end_sending(F) wherein F() does nothing.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_abafdb9a1294fe2160c61d48f1cd327ff"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#abafdb9a1294fe2160c61d48f1cd327ff">ipc::transport::Native_handle_sender::Native_handle_sender</a></div><div class="ttdeci">Native_handle_sender()</div><div class="ttdoc">Default ctor: Creates a peer object in NULL (neither connected nor connecting) state.</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1Native__handle__sender_html_ac96b0aa01c286d525f9dcfa6dacc4220"><div class="ttname"><a href="classipc_1_1transport_1_1Native__handle__sender.html#ac96b0aa01c286d525f9dcfa6dacc4220">ipc::transport::Native_handle_sender::send_native_handle</a></div><div class="ttdeci">bool send_native_handle(Native_handle hndl_or_null, const util::Blob_const &amp;meta_blob, Error_code *err_code=0)</div><div class="ttdoc">In PEER state: Synchronously, non-blockingly sends one discrete message, reliably/in-order,...</div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1sync__io_1_1Native__handle__receiver_html"><div class="ttname"><a href="classipc_1_1transport_1_1sync__io_1_1Native__handle__receiver.html">ipc::transport::sync_io::Native_handle_receiver</a></div><div class="ttdoc">A documentation-only concept defining the behavior of an object that is the sync_io-pattern counterpa...</div><div class="ttdef"><b>Definition:</b> <a href="sync__io_2native__handle__transport_8hpp_source.html#l00339">native_handle_transport.hpp:340</a></div></div>
<div class="ttc" id="aclassipc_1_1transport_1_1sync__io_1_1Native__handle__sender_html"><div class="ttname"><a href="classipc_1_1transport_1_1sync__io_1_1Native__handle__sender.html">ipc::transport::sync_io::Native_handle_sender</a></div><div class="ttdoc">A documentation-only concept defining the behavior of an object that is the sync_io-pattern counterpa...</div><div class="ttdef"><b>Definition:</b> <a href="sync__io_2native__handle__transport_8hpp_source.html#l00073">native_handle_transport.hpp:74</a></div></div>
<div class="ttc" id="aclassipc_1_1util_1_1Shared__name_html"><div class="ttname"><a href="classipc_1_1util_1_1Shared__name.html">ipc::util::Shared_name</a></div><div class="ttdoc">String-wrapping abstraction representing a name uniquely distinguishing a kernel-persistent entity fr...</div><div class="ttdef"><b>Definition:</b> <a href="shared__name_8hpp_source.html#l00241">shared_name.hpp:242</a></div></div>
<div class="ttc" id="anamespaceipc_1_1transport_html"><div class="ttname"><a href="namespaceipc_1_1transport.html">ipc::transport</a></div><div class="ttdoc">Flow-IPC module providing transmission of structured messages and/or low-level blobs (and more) betwe...</div><div class="ttdef"><b>Definition:</b> <a href="asio__local__stream__socket_8cpp_source.html#l00031">asio_local_stream_socket.cpp:32</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a6cb62ae434900f3a8915b33ec5d61a96"><div class="ttname"><a href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">ipc::util::Blob_mutable</a></div><div class="ttdeci">boost::asio::mutable_buffer Blob_mutable</div><div class="ttdoc">Short-hand for an mutable blob somewhere in memory, stored as exactly a void* and a size_t.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00140">util_fwd.hpp:140</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ac66141280c3b7295a86b65209f31cc58"><div class="ttname"><a href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">ipc::util::Fine_duration</a></div><div class="ttdeci">flow::Fine_duration Fine_duration</div><div class="ttdoc">Short-hand for Flow's Fine_duration.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00117">util_fwd.hpp:117</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ae0be7edba7e30ffa3f8b742af621f2ab"><div class="ttname"><a href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">ipc::util::Blob_const</a></div><div class="ttdeci">boost::asio::const_buffer Blob_const</div><div class="ttdoc">Short-hand for an immutable blob somewhere in memory, stored as exactly a void const * and a size_t.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00134">util_fwd.hpp:134</a></div></div>
<div class="ttc" id="anamespaceipc_html_aa3192e586cc45d3e7c22463bf2760f89"><div class="ttname"><a href="namespaceipc.html#aa3192e586cc45d3e7c22463bf2760f89">ipc::Error_code</a></div><div class="ttdeci">flow::Error_code Error_code</div><div class="ttdoc">Short-hand for flow::Error_code which is very common.</div><div class="ttdef"><b>Definition:</b> <a href="common_8hpp_source.html#l00298">common.hpp:298</a></div></div>
<div class="ttc" id="astructipc_1_1util_1_1Native__handle_html"><div class="ttname"><a href="structipc_1_1util_1_1Native__handle.html">ipc::util::Native_handle</a></div><div class="ttdoc">A monolayer-thin wrapper around a native handle, a/k/a descriptor a/k/a FD.</div><div class="ttdef"><b>Definition:</b> <a href="native__handle_8hpp_source.html#l00062">native_handle.hpp:63</a></div></div>
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